Class 12 Engineering Chemistry - The P-Block Elements

Fill in the blanks.
In solid state, nitrogen occurs as __________.

The only important nitrogen minerals are nitre (potassium nitrate, saltpetre) and sodanitre (sodium nitrate, Chilean saltpetre) which mans nitrogen occurs in nitrate state.

Nitrolium is used as fertiliser. Explain.

The main use of calcium cyanamide is in agriculture as a fertilizer. In contact with water it decomposes and liberates ammonia:

$CaC{ N }_{ 2 }+3{ H }_{ 2 }O\longrightarrow 2N{ H }_{ 3 }+CaC{ O }_{ 3 }$

(a) Draw the structures of the following:
(i) $Xe{F}_{2}$ (ii) $Br{F}_{3}$
(b) Write the structural difference between white phosphorus and red phosphorus?

Red Phosphorous looks similar to White Phosphorous, except it is made up of two tetrahedral groups of phosphorous, attached by one side. It is more stable than the white allotrope, which will slowly turn into red phosphorous, after being heated or in the presence of light.

Name one halogen of period.

Name of halogen

Fluorine (2) ; Chlorine(3) ; Bromine (4) ; Iodine (5) ; Astatine (6)

(a) Explain the Pauling scale for the determination of electronegativity. Give the disadvantages of Pauling scale.
(b) How does Fluorine differ from other halogens?

(a) Pauling's scale:
(i) Pauling scale is based on an emperical relation between the energy of a bond and the electronegativities of bonded atoms.
(ii) Consider a bond

$A-B$ between two dissimilar atoms

$A$ and

$B$ of a molecule

$AB$ . Let the bond energies of

$A-A,B-B$ and

$A-B$ bonds be represented as

${ E }_{ A-B }$ ,

${ E }_{ B-B }$ and

${ E }_{ A-B }$ respectively. It may be seen that the bond dissociation energy of

$A-B$ is almost higher than the geometric mean of the bond dissociation energies of

$A-A$ and

$B-B$ bonds i.e.,

${ E }_{ A-B }>\sqrt { { E }_{ A-A }\times { E }_{ B-B } }$
Their difference

$(\Delta)$ is related to the difference in the electronegativities of

$A$ and

$B$ according to the following equation:

$\Delta ={ E }_{ A-B }-\sqrt { { E }_{ A-A }\times { E }_{ B-B } } ={ \left( { X }_{ A }-{ X }_{ B } \right) }^{ 2 }$
or

$0.208$

$\sqrt { \Delta } ={ X }_{ A }-{ X }_{ B }$
Here

${X}_{A}$ and

${X}_{B}$ are the electronegativities of

$A$ and

$B$ respectively.
The factor

$0.208$ arises from the conversion of Kcals to electron volt.
(iii) Considering arbitarily the electronegativity of hydrogen to be

$2.1$ , Pauling calculated electronegativities of other elements with the help of this equation.
Disadvantage of Pauling scale: The disadvantage of Pauling's scale is that bond energies are not known with any degree of accuracy for many solid elements.
(b) (i) Fluorine is the most reactive elements among halogens. This is due to the minimum value of

$F-F$ bond dissociation energy.
(ii) Fluorine decomposes cold dilute alkali liberating

${F}_{2}O$ and with conc., alkali

${O}_{2}$ is liberated. Under similar conditions, other halogens will give rise to hypohalites and halates respectively.
(iii) Fluorine has the greatest affinity for hydrogen, forming

$HF$ which is associated due to the hydrogen bonding.

$HF$ is a weak acid where as other hydrohalic acids are strong acids.

$....H-F.....H-F......H-F$
(iv) It differs markedly from other halogens in that it can form two types of salts with metals

$NaF$ and

$NaH{F}_{2}$ .
(v) The salts of

$HF$ are different from the salts of other hydracids.

$AgF$ is soluble in water but other silver halides are not soluble in water.
(vi) Fluorine can have only negative oxidation state due to strong electronegativity character while other halogens can have negative as well as positibve oxidation states.
(vii)

$HF$ attacks glass while others do not
(viii) Fluorine does not form polyhalide because of absence of d orbitals. WHere as the other halogens form poly halides such as

${ I }_{ 3 }^{ - },{ Br }_{ 3 }^{ - },{ Cl }_{ 3 }^{ - }$ ions.

Calculate the effective nuclear charge of the last electron in an atom whose configuration is $1s^2 2s^2 2p^6 3s^2 3p^5$ .

Z = 17

$Z^* = Z-S$
= 17 - [(0.35

$\times$ No. of other electrons in nth shell)] + (0.85

$\times$ No. of electrons in (n - 1)th shell) + (1.00

$\times$ total number of electrons in the inner shells)

$= 17 - [(0.35 \times 6) + (0.85 \times 8) + (1 \times 2)]$

$= 17 - 10.9 = 6.1$

Write the names of Inert gases.

The names of inert (noble) gases include helium, neon, argon, krypton, xenon and radon. These gases are chemically unreactive and forms very few compounds.

With reference to Haber's process, write the equation and the conditions required.

The reaction involved is:

$N_2 (g)+3H_2(g) \rightarrow 2NH_3(g)$ ,

$\Delta H=-92KJmol^{-1}$

In the Haber process, nitrogen and hydrogen react together under these conditions: a high temperature - about 450ºC. a high pressure. an iron catalyst.

In the manufacture of nitric acid by Ostwald's process,___________ as a dehydrating agent is used to convert $68\%$ by mass of $HNO_3$ to $98\%$ by mass of $HNO_3$ ?

The dehydrating agent used to increase the concentration of

$HNO_3$ is

$H_2SO_4$ .

$H_2SO_4$ absorbs water from

$HNO_3$ and concentrated

$HNO_3$ is obtained.

What are noble gases? Name all in the order of their increasing density.

A group of gases which do not react chemically with any other substance are called noble gases. They are helium, neon, argon, krypton, xenon and radon.

$LiI$ is soluble in water but $LiF$ is not, why?

Due to small size of

$F^-$ ions ,the lattic enthalphy of Lif is very high ,but the hydration enthalphy of it is very less.so lif is insoluble in water in Licl ,since

$Cl^-$ is of large size and low lattice enthalpy and high hydration enthalpy so,it is soluble in water

In how many of the following species the central atom has two lone pairs of electrons ?
$XeF_4$
$Xe{F_{5}}^{-}$

$F_2SeO_2$
$Xe{F_{3}}^{+}$
$XeOF_4$

$ClOF_3$
$IC{l_{4}}^{-}$

$SCl_2$

$OSF_4$

It is likely that Ar will form the anion Ar $^-$ . If true enter 1, else enter 0.

Added electrons eneters 4s orbital of higher energy where it gets repulsion. Thus, (EA) value is positive. Thus, Ar

$^-$ is not formed.

Peroxonitrous acid is an unstable intermediate formed in the oxidation of $HNO_2$ by $H_2O_2$ .
"Peroxonitrous acid has the same formula as nitric acid, $HNO_3$ ."
Answer whether the above statement is true or false.If true enter 1, else 0.

The correct answer is 1.

Peroxonitrous acid is an unstable intermediate formed in the oxidation of

$HNO_2$ by

$H_2O_2$ .

Peroxonitrous acid is a weak acid with formula of

$HNO_3$ or

$HOONO$ and acts as a powerful oxidising agent.

The tendency to form clathrates decreases down the group.

Clathrates are crystalline water based solids, physically resembling ice. Clathrate formation does not involve formation of chemical bonds. Tendency to form Clathrates increases down the group due to increase in size.

Maximum acidic character is shown by the oxyacids of halogens with oxidation number of halogens as ____________ .

As oxidation no increases, acidic character increases. So, maximum acidic character is shown by compounds with oxidation state +7 since it is the highest oxidation state of halogen.

ncreasing order of bond energy: ${ F }_{ 2 }<{ Cl }_{ 2 }<{ O }_{ 2 }<{ N }_{ 2 }$
If true enter 1, else enter 0.

The increasing order of bond energy is

${ F }_{ 2 } (158 kJ/mol) <{ Cl }_{ 2 } (243 kJ/mol) <{ O }_{ 2 } (498.7 kJ/mol)<{ N }_{ 2 } (946 kJ/mol)$
(1) The bond energy decreases with increase in the number of lone pair of electrons on the bonded atom.
(2) As the number of multiple bonds increases, the bond energy increases.

In the following reaction
$XeF_2 + {BrO_3}^- + H_2O\longrightarrow Xe + {BrO_4}^- + 2HF$

$\displaystyle equivalent \:mass \:of \:{BrO_3}^-=\frac{molar \: mass}{..........}$

In the following reaction:

$XeF_2 + {BrO_3}^- + H_2O\longrightarrow Xe + {BrO_4}^- + 2HF$

$\displaystyle equivalent \:mass \:of \:BrO_3^-=\frac{molar \: mass}{2}$ .

The oxidation number of Br changes form +5 to +7. Hence, the net change in the oxidation number is 2.

Number of phases in the following equilibrium is
$Ra(s)\longrightarrow Rn( g) + He(g)$

The given equilibrium contains two phases one is solid and other is gas.

For inert monatomic gases, $\displaystyle \frac{C_P}{C_V}=\frac{5}{x}$ . The value of x is _____ .

For inert monoatomic gases,

$C_P = \dfrac {5}{2}R$

$C_V = \dfrac {3}{2}R$

$\displaystyle \frac{C_P}{C_V}=\dfrac{5}{3}$ .

Hence,

$x = 3$

When $Mg_3N_2$ react with $H_2O$ , then how many type of gaseous product(s) is/are formed ?

When

$Mg_3N_2$ react with

$H_2O$ , then one type of gaseous product (ammonia) is formed. The other product is magnesium hydroxide.

$Mg_3N_2 +H-OH \rightarrow Mg(OH)_2 +NH_3$

In $NO_3^-$ ion, find the number of bond pairs and lone pairs of electrons on nitrogen atoms.

[If the answer is 2 and 4, represent as 24]

$NO_3^-$ ion, the number of bond pair and lone pair of electrons on nitrogen atom are 4 and 0 respectively. Hence,the answer is 40.

Find the sum of atomicity of nitrogen and phosphorous.

Atomicity is the total number of atoms present in 1 molecule of a substance. The atomicity of nitrogen is 2 as

$N_2$ molecule contains 2 atoms. The atomicity of phosphorus is 4 as

$P_4$ molecule contains 4 atoms. Hence, the sum of the atomicity of nitrogen and phosphorus molecule is

$2+4=6$ .

Rank the bond length of the bond below in the molecules on the left column with longest as 1 and shortest as 4
Match the following.

Bond length increases as the % S-character decreases.In $$NO_3^- the % s character is minimum.

$NO_2^+$ % s character is maximum because of two double bonds .

$NO_2^-$ the - charge is dispersed due to resonance and has s character less than

$N_2O_4$ .

$N_2O_4$ has less s character than

$NO_2^+$

How many number of faces are there in $P_4$ molecule?

$P_4$ molecule has pyramidal geometry with four faces.

The electronic configuration of an element is $1s^2, 2s^2, 2p^6, 3s^2 3p^3$ . What is the atomic number (X) of the element which is just below the above given element in the periodic table. Enter the value of $X$ .

The electronic configuration

$1s^2, 2s^2, 2p^6, 3s^2 3p^3$ represents phosphorus with atomic number 15. Arsenic is just below phosphorus in the periodic table. Its atomic number is 33.

The atomicity of phosphorus is X and the P-P-P bond angle is Y. What are X and Y?
[If answers are $2$ and $90$ , represent as 290]

The atomicity of phosphorus is X and the P-P-P
bond angle is Y. X is equal to 4 and Y is equal to 60.
Hence, the answer is 460.

Observe the chemical reaction:

$P_4 + 3NaOH +3 H_2O \rightarrow$ $3NaH_2PO_2+PH_3$

If the reaction is true enter 1 else 0

Phosphorus reacts with aqueous alkalies to form sodium hypophosphite and phosphine.

$P_4+3NaOH+3H_2O \rightarrow 3NaH_2PO_2+PH_3$

sodium phosphine

hypophosphite

The given reaction is correct. Hence, the correct answer is 1.

In Nessler's reagent for the detection of ammonia, the active species is ______.
$H_2Cl_2$
$HgI_4^{2-}$

Nessler's reagent is used for the detection of ammonia or ammonium ion. When Nessler's reagent is added to the ammonia solution, brown colour precipitate is obtained.

The active species in this is

$HgI_4^{2-}$ .

Hence, the correct option is (2).

1922665_250446_ans_569a2177dcf34e608e156e70b4ca37d2.PNG

Write balanced chemical equations for the reaction of a burning of aluminum in the air.

The chemical equations for burning of Al in air can be written as:

$4Al + 3O_{2} \rightarrow 2Al_{2}O_{3}$

$2Al + N_{2} \rightarrow 2AlN$

Why is helium used in weather observation balloons?

Hydrogen is a highly combustible gas. Moreover, it is the lightest gas. When weather balloons move to high altitudes in the atmosphere, the air becomes thin and the protection of the ozone layer also decreases. So, sometimes, the ultraviolet radiations react with Hydrogen and can cause a blast.

With Helium, there are no such problems. You only have to sacrifice the level of altitudes you can reach. But considering safety, Helium has replaced Hydrogen in weather balloons.

Helium is the most abundant Noble gas in the universe
If this is true enter 1, if false enter 0.

Hydrogen is the most abundant element in the Universe; helium is second. Hydrogen and helium are estimated to make up roughly 74% and 24% of all baryonic matter in the universe respectively.

How is ammonia manufactured industrially?

Haber's process is used for manufacturing ammonia.

$\displaystyle N_2 (g) + 3_2(g) \rightleftharpoons 2NH_3(g)$

$\displaystyle \Delta _f H^o = - 46.1 \: kJ/mol$

Optimum conditions (to obtain maximum yield of ammonia) are around

$200$ atm pressure,

$700$ K temperature and a catalyst containing iron oxide with small amounts of

$\displaystyle K_2O$ and

$\displaystyle Al_2O_3$ . The reaction is reversible exothermic reaction and optimum conditions mentioned above are in accordance with Le Chatelier's principle.

Explain why fluorine forms only one oxoacid, HOF.

Fluorine forms only one oxoacid, HOF due to small atomic size and high electronegativity. Fluorine cannot act as central atom in higher oxoacids.

Give reasons for the following:
$R_{3}P = O$ exists but $R_{3}N = O$ does not, $R$ is an alkyl group?

Nitrogen cannot have covalency more than 4. This is the restriction which comes in nitrogen(N) to expand its coordination number beyond four. Hence,

$\displaystyle R_3N=O$ does not exist. But P can show covalency of 5. Hence,

$\displaystyle R_3P=O$ exists.

Nitrogen cannot form

$\displaystyle d \pi - p \pi$ bonds but phosphorous can form

$\displaystyle d \pi- p \pi$ bonds.

How are xenon fluorides $XeF_{2},\ XeF_{4}$ and $XeF_{6}$ obtained?

The preparation of xenon fluorides are given below:

$\displaystyle Xe_{(g, excess)} + F_{2(g)} \xrightarrow [1\ bar] {673\ K} XeF_{2(s)}$

$\displaystyle Xe_{(g,1 mole)} +2F_{2 (g, 5\ moles)} \xrightarrow [7\ bar]{873\ K} XeF_{4(s)}$

$\displaystyle Xe_{(g, 1\ mole)} + 3F_{2 (g, 20\ moles)} \xrightarrow {60-70\ bar} XeF_{6 (s)}$

Two elements 'P' and 'Q' belong to the same period of the modern periodic table and are in Group 1 and Group 2, respectively. Compare their following characteristics in tabular form.
(a) The number of electrons in their atoms
(b) The sizes of their atoms
(c) Their metallic character
(d) Their tendencies to lose electrons
(e) The formula of their oxides
(f) The formula of their chlorides

Group 1	Group 2
a) One electron in the valence shell	Two electrons in the valence shell
b) Larger atomic size compared to Group 2	Smaller atomic size compared to Group 1
c) More metallic in nature	Comparatively less metallic
d) Highly electropositive, readily loses electron	Comparatively less electropositive
e) Oxide formula: $X_2O$	Oxide formula: $XO$
f) Chloride formula: $XCl$	Chloride formula: $XCl_2$

(a)Account for the following:
(i)Acidic character increase from $HF$ to $HI$ .
(ii)There is a large difference between the melting and boiling points of oxygen and sulphur.
(iii) Nitrogen does not form pentahalide.
(b) Draw the structures of the following:
(i) $ClF_3$
(ii) $XeF_{4}$

(a)

(i) Size of halide ions order

$F^-<Cl^-<Br^-<I^-$ with increase size negative charge is dispered throughout ions and ions gets stabilized. Thus acidity order

$HF<HCl<HBr<HI$

(ii) Due to present of vacant d-orbital and combining forms of sulphur (

$S_8$ ) which are not occurs in oxygen, the cohesive energy of sulphur more than oxygen leading to large melting point and boiling point

(iii) Due to absent of d-orbital, nitrogen can not extend its octate to form pentahalide.

Phosphorus has valencies of 3 and 5.
What is the formula of the two oxides of phosphorus?

The two common oxides of phosphorus are

$P_4O_6$ (phosphorus trioxide/tetraphosphorus hexoxide), in which phosphorus has valency 3, and

$P_4O_{10}$ (phosphorus pentoxide/tetraphosphorus decaoxide), in which phosphorus has valency 5.

Draw the structures of the following molecules:
(i) $N_{2}O_{5}$ (ii) $XeF_{2}$

Account for the following:
(i) $Bi\left(V\right)$ is a stronger oxidizing agent than $Sb\left(V\right)$ .
(ii) $N-N$ single bond is weaker than $P-P$ single bond.
(iii) Noble gases have very low boiling points.

(i) Bi has larger size than Sb. So the outer most electron are held less strongly, so they interact with other atom more easily. Hence, Bi(V) is stronger oxidizing agent than Sb(V).

(Ii) N has smaller size so lone pair is more concentrated over N hence repulsion take place and bond becomes weak but P has large size therefore, no repulsion takes place. Hence, bond become strong.

(iii) Noble gas are monoatomic with weak vander wall's force of attraction. Hence, noble gas has very low boiling point.

Draw the structures of the following molecules:
(i) $XeF_{6}$ (ii) $H_{2}S_{2}O_{7}$

ii.

(a) Draw the structures of the following molecules:
(i) $XeO{F}_{4}$
(ii) ${H}_{2}S{O}_{4}$
(b) Write the structural difference between white phosphorus and red phosphorus.

(a) Draw structure of the following compounds:
(i) $Xe{F}_{4}$ (ii) ${N}_{2}{O}_{5}$
(b) Write the structural difference between white phosphorus and red phosphorus.

Red Phosphorous looks similar to white phosphorous, except it is made up of two tetrahedral groups of phosphorous, attached by one side. It is more stable than the white allotrope, which will slowly turn into red phosphorous, after being heated or in the presence of light.

Name a compound of chlorine that is used as:
(A) An disinfectant (B) An anesthetic (C) A bleaching agent

(a) Sodium hypochlorite

$(NaOCl)$ is a commonly used disinfectant used for water purification.

(b) Chloroform

$(CHCl_3)$ is a sweet-smelling liquid that is used as a sedative and anesthetic.

$(CaOCl_2)$ is a powerful bleaching agent that removes stains by oxidizing coloured substances.

Chlorine does not exist in free state. Give reason.

Because chlorine is highly electronegative as it requires only one electron for stable and complete octet. It will react readily and form a stable diatomic molecule.

Ammonia gas is collected by ______.
(an upward displacement of air, a downward displacement of water, a downward displacement of air)

Since ammonia gas is lighter than air, it is collected by downward displacement of air.

Some word/ words are missing in the following statements. You are required to rewrite the statements in the correct form using the appropriate word/ words:
Magnesium nitride reacts with water to liberate ammonia.

Magnesium nitride reacts with boiling water to liberate ammonia gas. Here boiling water is very important in order to initiate the reaction.

Study the figure given below and answer the questions that follow:
Name another gas which has the same property and can be demonstrated through this experiment.

The fountain experiment can also be done for ammonia gas. Here, instead of blue litmus solution, reda litmus solution is used. We get blue coloured fountain for ammonia gas. This shows high solubility of ammonia in water and also the alkaline nature of ammonia gas.

Copy and complete the following table relating to important industrial process:
Name of the process Temperature Catalyst Equation for the
catalyzed reaction
Haber's process

Haber's process is used for the preparation of ammonia.

Temperature :

$450^{\circ} C - 500^{\circ} C$ .

Catalyst : Finely divided iron. Also molybdenum is used as a promoter.

Equation :

$N_2 + 3H_2 \rightarrow 2NH_3 + \Delta$

The following questions are based on the preparation of ammonia gas in the laboratory:
Explain why ammonium nitrate is not used in the preparation of ammonia?

Ammonium nitrate is a highly explosive substance. Hence, the risk of heating it cannot be taken.

The following questions are based on the preparation of ammonia gas in the laboratory:
Name the compound normally used as a drying agent during the process.

$CaO$ is a hydroscopic salt. It readily absorbs the moisture. Hence, it is commonly used drying agent.

The following questions are based on the preparation of ammonia gas in the laboratory:
How is ammonia gas collected?

Ammonia is lighter than air hence it displaces air downward. It is highly soluble in water and hence cannot be collected over water.

The following questions are based on the preparation of ammonia gas in the laboratory:
Explain why it is not collected over water?

Ammonia cannot be collected over water as it is highly soluble in water. It is collected by downward displacement of air being lighter than air.

Explain how does nitrogen exhibit anomalous behaviour amongst group $15$ elements.

Anomalous behaviour of nitrogen among group

$15$ elements.
Nitrogen is the first amongst group

$15$ elements, which has,
(i) The smallest atomic size.
(ii) Highest electronegativity.
(iii) The highest ionisation energy, and
(iv) Absence of d-orbitals.
The difference in the nature between nitrogen and other elements of

$15$ grou are:
(i) Nitrogen is a gas while all the other elements are solid.
(ii) Nitrogen exists as diatomic molecule,

$(N_2)$ while other elements exist as tetraatomic molecules(

$P_4, As_4, Sr_4$ , etc)
(iii) Being the highest electronegativity, nitrogen forms hydrogen bonding while other doesn't.
(iv) Nitrogen forms

$p\pi - p\pi$ multiple bonds while other elements in the group from

$p\pi - d\pi$ multiple bonds.
(v) Nitrogen shows wide range of oxidation states from

$-3$ to

$+5$ while other elements show limited oxidation states.
(vi)

$NH_3$ is basic while other hydrides are very less basic.
(vii)The trihalides of nitrogen(except

$NF_3$ ) are unstable while the trihalides of the other elements are comparatively stable.
(viii) Except nitrogen, all other elements have vacant d-orbitals, and due to this nitrogen doesn't undergo formation of coordination compound.

Describe anomalous behaviour of fluorine with the other elements of group $17$ with reference to:
Hydrogen bonding.

Anomalous behaviour of fluorine with the other elements of group

$17$ : Fluorine shows anomalous behaviour with the other elements of group

$17$ due to :

$(1)$ small size,

$(2)$ high electronegativity and

$(3)$ non-availability of d-orbitals in its valence shell.
(a) Hydrogen bonding: On account of high electronegativity of fluorine atoms, extensive hydrogen bonding occurs in

$HF$ molecule while it is absent in

$HCl, HBr$ and

$HI$ . The presence of hydrogen bonding in

$HF$ is explained as under:

$(1) HCl, HBr$ and

$HI$ are gaseous while

$HF$ is a liquid with an abnormally high boiling point.

$(2)$

$HF$ forms a number of compounds containing

$HF_{2}^{-}$ ion (e.g.

$KHF_{2}$ ) while such compounds are not given by other

$HX$ molecules.

$H-F\ H-F\ \underset {\underset {H-bond}{\uparrow}}{H-F} (HF)_{n}$

Why nitrogen exists as diatomic molecule $(N_2)$ and Phosphorus as $P_4$ ?

Nitrogen exists as diatomic molecule (N

$\displaystyle _2$ ) with triple bond between two N atoms and phosphorus as P

$\displaystyle _4$ . Nitrogen can form

$\displaystyle p\pi-p\pi$ multiple bonds. Phosphorous cannot form such bonds due to repulsion between non bonded electrons of inner core. In case of nitrogen, there is no such repulsion as it has only 1s electrons in inner shell so that the overlap of p orbitals to form pi bonds is easy.

Give balanced equations and principle involved in the manufacture of nitric acid $(HNO_{3})$ by Ostwald's process.

Ammonia is oxidized by atmospheric oxygen using catalyst.

$\displaystyle 4NH_3(g) +5O_2(g) \xrightarrow [500K, \: 9 bar]{Pt/Rh \: gauge \: catalyst} 4NO(g)+6H_2O(g)$
Nitric oxide reacts with oxygen to form nitrogen dioxide

$\displaystyle 2NO(g) +O_2(g) \rightleftharpoons 2NO_2(g)$
Nitrogen dioxide dissolves in water to form nitric acid.

$\displaystyle 3NO_2(g)+H_2O(g) \rightarrow 2HNO_3(l)+NO(g)$
NO formed as byproduct is reused and aqueous

$\displaystyle HNO_3$ is concentrated by distillation up-to 68% by mass. It is then dehydrated with water to form 98% by mass.

Describe anomalous behaviour of fluorine with the other elements of group $17$ with reference to:
Polyhalide ions.

Anomalous behaviour of fluorine with the other elements of group

$17$ : Fluorine shows anomalous behaviour with the other elements of group

$17$ due to :

$(1)$ small size,

$(2)$ high electronegativity and

$(3)$ non-availability of d-orbitals in its valence shell.
Polyhalide ions: Because of the absence of d-orbitals in its valence shell fluorine does not combine with

$F^{-}$ ions to give polyhalide ions (like

$F_{3}^{-}$ ) while other members of group

$17$ give such polyhalide ions like

$Cl_{3}^{-}, Br_{3}^{-}, I_{3}^{-}, I_{5}^{-}$ etc. because they contain d-orbitals and also there electronegativity is low.

a) Write a chemical equation to prepare ammonia from ammonium chloride?
b) Write a chemical equation to identify $Cu^{+2}$ & $Ag^+$ ions with the application of $NH_3$ ?
c) Draw a labeled diagram showing flowchart for the manufacture of ammonia?

a) The chemical equation to prepare ammonia from ammonium chloride is

$\displaystyle 2NH_4Cl +Ca(OH)_2 \rightarrow CaCl_2 +2H_2O +2NH_3 \uparrow$

b) Chemical equations to identify Cu

$^{+2}$ & Ag

$^+$ ions with the application of NH

$_3$ :

$\displaystyle AgCl + 2NH_4OH (excess) \rightarrow [Ag(NH_3)_2]Cl + H_2O$

$\displaystyle CuSO_4+2NH_4OH \rightarrow Cu(OH)_2 \downarrow +(NH_4)_2SO_4$

$\displaystyle Cu(OH)_2 +4 NH_4OH(excess) \rightarrow [Cu(NH_3)_4](OH)_2+4H_2O$

c) Flowchart for the manufacture of ammonia by Haber process is as shown.

$\displaystyle N_2+3H_2 \rightleftharpoons 2NH_3$

Write the chemical formulae of four oxy acids of chlorine.

The chemical formulae of four oxy acids of chlorine is as shown.
Hypochlorous acid

$\displaystyle HClO$
Chlorous acid

$\displaystyle HClO_2$
Chloric acid

$\displaystyle HClO_3$
Perchloric acid

$\displaystyle HClO_4$

Describe anomalous behaviour of fluorine with the other elements of group $17$ with reference to:
Oxidation state.

Anomalous behaviour of fluorine with the other elements of group

$17$ : Fluorine shows anomalous behaviour with the other elements of group

$17$ due to :

$(1)$ small size,

$(2)$ high electronegativity and

$(3)$ non-availability of d-orbitals in its valence shell.
Oxidation state: Due to maximum electronegativity of fluorine, it show only a negative oxidation state of

$-1$ . It does not show any positive oxidation state. The other members of group

$17$ show negative as well as positive oxidation states of

$+1, +3, +5$ and

$+7$ .

How are $Xe{F}_{2}$ and $Xe{F}_{4}$ prepared? Give their structures.

A mixture of xenon and fluorine (2:1) is passed through nickel tube at 400 deg C.

$\displaystyle Xe+F_2 \xrightarrow [Ni]{400^oC} XeF_2$

$\displaystyle XeF_2$ has linear structure with

$\displaystyle XeF_2$ bond angle of

$\displaystyle 180^0$ . Xe atom has 2 bond pairs and 3 lone pairs of electrons. Xe atom is

$\displaystyle sp^3d$ hybridized.

A mixture of xenon and fluorine ( 1:5) is passed at 400 deg C and 5-6 atm.

$\displaystyle Xe+2F_2 \xrightarrow [\text {5-6 atm}]{400^oC} XeF_4$

$\displaystyle XeF_4$ has square structure with

$\displaystyle XeF_4$ bond angle of

$\displaystyle 90^0$ . Xe atom has 4 bond pairs and 2 lone pairs of electrons. Xe atom is

$\displaystyle sp^3d^2$ hybridized.

Write the balanced Chemical equation with condition involved in manufacture of nitric acid by ostwald's process.

The balanced Chemical equation with condition involved in manufacture of

$nitric$

$acid$ by ostwald's process are as shown.

$\displaystyle 4NH_3(g)+5O_2(g) \xrightarrow [500 \: K \: 9 \: bar]{Pt/Rh \; gauge \: catalyst} 4NO(g) +6H_2O(g)$

$\displaystyle 2NO(g) +O_2(g) \rightleftharpoons 2NO_2(g)$

$\displaystyle 3NO_2(g) +H_2O(g) \rightarrow 2HNO_3(l) + NO(g)$

Write the equations involved in the preparation of nitric acid by Ostwald's process by maintaining the reaction conditions.

The balanced chemical equation with condition involved in manufacture of nitric acid by ostwald's process are as shown.

$\displaystyle 4NH_3(g)+5O_2(g) \xrightarrow [500 \: K \: 9 \: bar]{Pt/Rh \; gauge \: catalyst} 4NO(g) +6H_2O(g)$

$\displaystyle 2NO(g) +O_2(g) \rightleftharpoons 2NO_2(g)$

$\displaystyle 3NO_2(g) +H_2O(g) \rightarrow 2HNO_3(l) + NO(g)$

Nitrogen does not form pentahalides. Give reason.

$\displaystyle Nitrogen$ does not form pentahalides.
The electronic configuration of

$\displaystyle nitrogen$ is

$\displaystyle 1s^2 2s^2 2p^3$ .
It has 5 valence electrons. In the valence shell, it has s and p orbitals.

$\displaystyle Nitrogen$ does not has vacant d orbitals. It cannot expand its octet. In other words, it cannot have more than 8 valence electrons. Hence,

$\displaystyle nitrogen$ cannot be pentavalent .

For the manufacture of Ammonia by Haber's process, write the equation and optimum conditions for maximum yield of ammonia.

$NH_3$ is manufactured by Haber’s process. In this process, pure nitrogen and hydrogen gases react in the ratio of $1:3$ by volume in $400^0C-500^0C$ temperature, $200-900$ atm pressure in presence of iron as catalyst and molybdenum as promoter.

$N_2+3H_2\xrightarrow[Fe/Mo]{400-500^0C}2NH_3+Heat$

Discuss Haber's process for industrial manufacture of ammonia.

Industrial production of ammonia gas is carried out by Haber's process. In this method, dihydrogen and dinitrogen gases are mixed in

$3:1$ proportion by volume and then passed over iron catalyst at

$200-300$ bars of pressure. Temperature about

$773$ K is maintained during this reaction. Substances like

$Al_2O_3, K_2O$ are added to increase the efficiency of the catalyst. Hence, they are called promoters. By cooling the reaction mixture at temperature lower than

$273$ K, ammonia can be separated from the unreacted

$N_2$ and

$H_2$ gases. Thus, ammonia is obtained in the liquid form and

$N_2$ and

$H_2$ remain without reaction and can be used again to take part in the reaction.

$N_2(g)+3H_2(g)\overset{773K}{\underset{200-300bar[Fe]}{\longrightarrow}}2NH_3(g)+Heat$ .

Write the name of radioactive halogen?

The name of radioactive halogen is Astatine. It's chemical symbol is

$\displaystyle At$ . Its atomic number is

$85$ . It belongs to sixth period and 17th group of the periodic table. Its electronic configuration is

$\displaystyle [Xe]4f^{14}5d^{10}6s^26p^5$

Draw labelled diagram of Haber process for the manufacture of ammonia and write chemical equation?

Chemical equation:

${ N }_{ 2 }+3{ H }_{ 2 }\overset { { Fe }/{ { M }_{ 0 } } }{ \underset { 500,High\quad pressure }{ \rightleftharpoons } } 2N{ H }_{ 3 }+22,400$ calorie

The diagram showing the laboratory preparation of ${NH}_{3}$ is given.
(a) What are the reactants used?
(b) Why $CaO$ is used?
(c) What is the reason behind not keeping the jar in the upward direction?
(d) Write an experiment to identify presence of ${NH}_{3}$ in the gas jar.

(a) Ammonium chloride and calcium hydroxide
(b) To get dry ammonia, the gas is passed through drying the tower containing lumps of

$CaO$ .
(c) It is collected by the downward displacement of air because it is lighter than air.
(d) Fountain experiment
Being basic, ammonia gas changes red litmus solution blue.

Describe Haber process for the manufacture of ammonia?

The Haber Process combines nitrogen from the air with hydrogen to form ammonia. The reaction is reversible and the production of ammonia is exothermic. The following reaction takes place in the reactor.

$\\ { N }_{ 2(g) }+{ H }_{ 2(g) }\rightleftharpoons 2N{ H }_{ 3(g) }$

At each pass of the gases through the reactor, only about 15% of the nitrogen and hydrogen converts to ammonia. Gases are cooled and ammonia turns into liquid. Liquid ammonia is separated and rest of the gas is recycled. By continual recycling of the unreacted nitrogen and hydrogen, we get about 98% of ammonia.

Fluorine always shows-1 oxidation state. Why?

Fluorine always shows-1 oxidation state as it is most electronegative element. It has seven valence electrons and gains one valence electron to complete its octet. This gives

$\displaystyle -1$ oxidation state to fluorine.

Some elements in $p$ -block shows allotropy.
(a) What are the allotropic forms of sulphur?
(b) (i) How will you manufacture Sulphuric Acid by contact process?
(ii) What are inter halogen compounds?

a) Allotropic forms of sulfur are monoclinic, plastic and orthorhombic sulfur.

b) ii) An interhalogen compound is a molecule which contains two or more different halogen atoms (fluorine, chlorine, bromine, iodine, or astatine) and no atoms of elements from any other group, e.g., $ClF,IF_7$ .

(a) Account for the following:
(i) ${H}_{2}O$ is a liquid while ${H}_{2}S$ is a gas.
(ii) Noble gases have very low boiling points.
(iii) $N{O}_{2}$ dimerises to ${N}_{2}{O}_{4}$ .
(b) (i) What are interhalogen compounds?
(ii) Suggest any two examples on interhalogen compounds.

(a) (i)

$H_2O$ is liquid while

$H_2S$ is a gas because sulfur is less electronegative than oxygen and S-H bond is less polar than O-H bond.

Electronegativity of $H,\ O$ and $S$ are 2.2,3.44 and 2.58 respectively.
The difference in $H$ and $S$ is very less.So,they have dipole-dipole bonding.
$H_2O$ is having hydrogen bonding so it exists in liquid form while $H_2S$ having dipole-dipole bonding ,so exists in gas form at room temperature.

(a) (ii) Noble gases have very low boiling point due to weak inter-atomic forces.The reason of having less inter-molecular force is,they are monoatomic and unpolarised.

(a) (iii)

$NO_2$ contains odd number of valence electrons.It behaves as an odd electron-molecule.Therefore,it goes toward the dimerisation to form stable molecule.

(b) (i) Any molecule which contains two or more different halogen atoms and no atoms of elements from any other group known as inter-halogen compounds.

Generally they known as binary, formula is $xy_n$ whose $n=1,3,5$ or 7 and $x$ is less electronegative than $y$ .

(b) (ii) Examples :

$xy$ type- $BrCl,BrF$
$xy_3$ type - $ClF_3,BrF_3$

Why the elements of group 17 are coloured?

The halogens' colors are results of the absorption of visible light by the molecules, which causes electronic excitation. Fluorine absorbs violet light, and therefore appears light yellow. Iodine, on the other hand, absorbs yellow light and appears violet (yellow and violet are complementary colors, which can be determined using a color wheel). The colors of the halogens grow darker down the group:

Fluorine - pale yellow/brown

Chlorine - pale green

Bromine - red-brown

Iodine - violet

Astatine* - black/metallic

Explain the industrial preparation of ammonia by Haber's process. Also, write two physical properties of ammonia.

Industrial production of ammonia gas is carried out by Habers process. In this method, dihydrogen and dinitrogen gases are mixed in 3:1 proportion by volume and then passed over iron catalyst at 200-300 bars of pressure. A temperature of about 773 K is maintained during this reaction. Substances like

$Al_2O_3, K_2O$ are added to increase the efficiency of the catalyst. Hence, they are called propmoters. By cooling the reaction mixture at a temperature lower than 273 K, ammonia can be separated from the unreacted

$N_2$ and

$H_2$ gases. Thus, ammonia is obtained in the liquid form and

$N_2$ and

$H_2$ remain without reaction and can be used again to take part in the reaction.

$N_2(g)+3H_2(g) \xrightarrow [200-300 bar / Fe ]{773K} 2NH_3(g) + heat$

Physical properties of ammonia: Ammonia is a colourless gas. It possesses a very intensive smell, causing irritation in the nose and the eyes.

What are inter-halogen compounds?

Covalent compounds formed by combination of two or more different halogen atoms are called interhalogen compounds.

Give a reason for the following.
Inert gases do not form ions.

The electronic configuration of inert gases is

$ns^2np^6$ . Therefore they have completely filled orbitals that imparts high stability to the gases and thus they don't ionize.

What are allotropes? Write the names of allotropes of phosphorus.

Allotropes are the different physical forms in which an element can exist. Allotropy is a property by which an element can exist in different forms having different physical properties.

Allotropes of phosphorus include white (or yellow) phosphorus, red (or violet) phosphorus, black phosphorus.

Describe industrial manufacture of ammonia by Haber's process with labelled diagram.

Large scale production of ammonia is carried by Haber's process as:

${ N }_{ 2 }\quad (g)+\ 3{ H }_{ 2 }\ (g)\ \rightleftarrows \ 2{ NH }_{ 3 } (g)$

$\displaystyle \Delta H_f = -46.1$ kJ/mol

In the process, the two gases (

${ N }_{ 2 }\quad and { \quad H }_{ 2 }$ ) are mixed in a molar ratio of

$1:3$ and then compressed to the pressure of 200 atm. The mixture then reacts on Iron oxide catalyst (highly porous and finely divide) containing small amounts of promoters (molybdenum or alumina (

${ Al }_{ 2 }{ O }_{ 3 }$ ) and potassium oxide (

${ K }_{ 2 }{ O }$ ). The reaction is carried out at a high temperature of about 700 K. The ammonia gas is obtained which is then cooled to liquid ammonia and the unreacted molecules of

$N_2$ and

$H_2$ are directed back to the compression chamber.

Explain why:
Nitrogen does not form pentahalides.

Valence shell elelctronic configuration of

$N$ is

$2s^22p^3$ . Therefore, it can accomodate maximum of three electrons in its valence p-orbital. As

$N$ doesnot have any d-orbital unlike P, therefore can not expand its octet and doesnot form pentahalides.

Explain why:
Hydride of sulphur is a gas while hydride of oxygen is a liquid.

Hydride of sulphur is

$H_2S$ and that of oxygen is

$H_2O$ . Since oxygen being highly electronegative has a tendency to form hydrogen bond, thereby increases the intermolecular interaction through extensive H-bonding. While,

$S$ can not undergo H-bonding and this explains the liquid phase of water and gaseous phase of

$H_2S$ .

$40$ ml of ammonia gas was taken in a eudiometer tube and subjected to sparks till the volume did not further change. The volume was found to increase by $40$ ml. $40$ ml of oxygen gas then mixed and the mixture was further exploded. The gases remaining were $30$ ml. Deduce the formula of ammonia. (Ammonia contains $N$ and $H$ only)

Let he formula be

$N_xH_y$

$N_xH_y \rightarrow \dfrac{x}{2} N_2 +\dfrac{y}{2}H_2$

The equation is,

$\dfrac{x}{2}\times40 +\dfrac{y}{2}\times40=80$

$x+y=4 -----(1)$

Now

$N_2$ is left and

$H_2$ reacts with

$O_2$ to form water

$H_2 +\dfrac{1}{2}O_2 \rightarrow H_20$

$\dfrac{x}{2}\times40 +40-10y=30$

Since volume left will be the combination of

$N_2$ and

$O_2$ left

$2x-y=-1----(2)$

Solving 1 and 2 we get

$x=1$

$y=3$

Thus the formula is

$NH_3$

Why ${ PCl }_{ 5 }$ exists but ${ NCl }_{ 5 }$ does not ?

$PCl_5$ forms five bonds by using the d-orbitals to "expand the octet" and have more "places" to put bonding pairs of electrons as it is an element of the 3rd period.

$NCl_5$ does not exist because it is an element of the 2nd period and there are no d-orbitals in the second energy level. Therefore there is no way to arrange five pairs of bonding electrons around a nitrogen atom.

Mention any two reasons for the anomalous behaviour of oxygen.

Reasons for the anomalous behavior of oxygen are given below.

1) Oxygen is small in size.

2) Oxygen has high electronegativity.

3) The valence shell of oxygen lacks vacant d orbitals.

Write the structure of chlorous acid $[HOClO]$ .

The structure of chlorous acid is as shown. It has one

$Cl=O$ double bond and one

$Cl-O$ single bond.

Explain allotropes of phosphorous.

There are several allotropes of phosphorous such as white phosphorous, red phosphorous and black phosphorous. In gaseous state ( and as waxy soild), white phosphorus has reactive

$P_4$ tetrahedra. Red phosphorous has complex chain structure which is formed by opening of

$P_4$ cage. Black phosphorous has a layer structure and is the most thermodynamically stable.

Find number of $p\pi-d\pi$ bonds in
(a) Disulphate (b) triphosphate (c) trimetaphosphate (d) trimer of ${SO}_{3}$ (e) ${P}_{4}{O}_{10}$ (f) ${P}_{4}{O}_{6}$

1424460_1066945_ans_856c65eab5da41f5b6ddb38514533a9d.png

In Haber process 30 litres of dihydrogen and 30 litres of dinitrogen were taken for reaction which yielded only 50% of the expected product. What will be the composition of gaseous mixture under these condition in the end.

Initial,

$3H_2+N_2\longrightarrow 2NH_3$

$30L$

$10L$

$\longrightarrow \cfrac {2}{3}\times 30=20$ {vol.

$\propto$ mol, PV=nRT}

$NH_3\longrightarrow 50$ %

$\Rightarrow20\times \cfrac {50}{100}=10L$

$NH_3$

$N_2=\cfrac {10}{2}=5L$ left=

$2.5L$

$H_2$ left=

$30-\cfrac {10}{2}\times3=15L$

$NH_3=\cfrac {1}{2}\times 20=10L$

$NH_3$

Sea is the greatest source of halogens. Comment.

Seawater contains chlorides, bromides, and iodides of Na, K, Mg, and Ca. However, it primarily contains NaCl. The deposits of dried up sea beds contain sodium chloride and carnallite, $KCl.MgCl_2.6H_2O.$
Marine life also contains iodine in their systems. For example, seaweeds contain up to 0.5% iodine as sodium iodide. Thus, the sea is the greatest source of halogens.

What change in colour is observed when white silver chloride is left exposed in sunlight? State the type of chemical reaction and also write its chemical equation.

When silver chloride is left exposed in sunlight, it decomposed to black metallic color silver and chlorine gas is evolved.

$2AgCl\longrightarrow 2Ag(s)+Cl(g)$

This is called as Photo decomposition Reaction.

Which allotropic form of phosphorus has discrete tetrahedral ${P_4}$ molecules.

Yellow and white phosphorous have tetrahedral

$P_4$ molecule.
1157764_1004523_ans_79ca27ca21d04ef7a9fb87d09f4ffa74.PNG

Solid phosphorus melts and evaporates at high temperature Gaseous phosphorus effuses at a rate that is $0.567$ times that of Ne in the same apparatus under the same conditions . How many atoms are in a molecule of gaseous phosphorus.

Let

${r}_{P}$ and

${r}_{Ne}$ be th rate of effusion of phosphorous and neon respectively.

Given that phosphorus effuses at a rate that is

$0.567$ times that of Ne in the same apparatus under the same conditions.

$\therefore \; {r}_{P} = 0.567 \times {r}_{Ne}$

As we know that, rate of effusion, 'r', of any gas of molar mass 'M' is given by-

$r = \cfrac{1}{\sqrt{M}}$

$\therefore \; {r}_{Ne} = \cfrac{1}{\sqrt{{M}_{Ne}}} = \cfrac{1}{\sqrt{20.18}} = 0.222$

Substituting the value of

${r}_{Ne}$ in

${eq}^{n} \left( 1 \right)$ , we have

${r}_{P} = 0.222 \times 0.567 = 0.126$ .

From the formula,

${r}_{P} = \cfrac{1}{\sqrt{{M}_{{P}_{n}}}}$

$\sqrt{{M}_{{P}_{n}}} = \cfrac{1}{{r}_{P}} = \cfrac{1}{0.126} = 7.93$

$\Rightarrow \; {M}_{{P}_{x}} = {\left( 7.93 \right)}^{2} = 62.88$

$n{\left( P \right)} = \cfrac{62.88 \; {g}/{mol}}{31 \; {g}/{mol}} \approx 2$

Hence there are

$2$ atoms in a molecule of gaseous phosphorus.

Find number of $p\pi -d\pi$ bonds in:
a) Disulphate b) Triphosphate c) Trimetaphosphate
d) Trimer of ${ SO }_{ 3 }$ e) ${ P }_{ 4 }{ O }_{ 10 }$ f) ${ P }_{ 4 }{ O }_{ 6 }$

(a) Disulphate (Refer to Image 1)

$\Rightarrow P \pi- d\pi$ bonds=

$4$

(b) Triphosphate (Refer to Image 2)

$\Rightarrow P\pi-d\pi$ bonds=

$3$

$\Rightarrow P \pi-d\pi$ bonds=

$3$

(d) Trimer of

$SO_3$ (Refer to Image 4)

$\Rightarrow P \pi-d \pi$ bonds=

$6$

(e)

$P_4O_{10}$ (Refer to Image 5)

$\Rightarrow P\pi-d \pi$ bonds =

$4$

(f)

$P_4O_6$ (Refer to Image 6)

$\Rightarrow P\pi-d\pi$ bonds=

$0$

$P \pi-d \pi$ overlaps forms doubel bonds.

1210336_1094369_ans_6a9d6912bb3e427da47ae991db88f501.png

From the artg of the periodic table given, answer the following questions
$1$ litium $2$ $13$ $14$ Carbon $15$ $16$ Oxygen $17$ $18$ neon
$X$ $S$ $P$ $L$
$Y$ $Q$
$Z$ $R$
$T$
Name the family of $L,Q,R,T$ .

Name of the family is halogen family that contains

$L=$ chlorine,

$Q=$ bromine,

$R=$ iodine and

$T=$ astatine. The

$17th$ group belongs to halogen family and the first number is fluorine with atomic no.

$9$ .

Explain Haber's process and manufacture of ammonium.

Ammonia is a colourless pungent smelling gas used mostly in production of fertilizers. It is widely manufactured by Haber process from nitrogen

$(N_2)$ and hydrogen

$(H_2).$ The Haber process takes nitrogen gas from air and combines it with molecular hydrogen gas to form ammonia gas. Nitrogen and hydrogen are taken in the ratio of 1:3 by volume. This is an exothermic reaction, it releases energy so that the sum of the enthalpies of

$N_2$ and

$H_2$ (the reactants) is greater than the enthalpy of

$NH_3$ (the products).

$N_2 (g) + 3H_2 (g) → 2NH_3 (g)$ ,

$ΔH = — 92 KJmol^{-1}$

(this is a reversible reaction)

The reaction is effected by temperature, pressure and catalyst on the composition of the equilibrium mixture, the rate of the reaction and the economics of the process. The catalyst is actually slightly more complicated than pure iron. It has potassium hydroxide added to it as a promoter — a substance that increases its efficiency.

1079854_1106932_ans_e7ff9afef19842cdb41f53c01f49e114.gif

Explain why nitrogen is much less reactive than phosphorous?

Nitrogen is chemically less reactive. This is because of the high stability of its molecule,

$N_2$ . In

$N_2$ , the two nitrogen atoms form a triple bond. This triple bond has very high bond strength, which is very difficult to break. It is because of nitrogen's small size that it is able to form

$p\pi-p\pi$ bonds with itself. This property is not exhibited by atoms such as phosphorus. Thus, phosphorus is more reactive than nitrogen.

If we have 24g of nitrogen how much hydrogen atom is required to form ammonia?

$N_2+3H_2\rightleftarrows 2NH_3$

$1$ mole of Nitrogen requires

$3$ moles of Hydrogens

$28g$ requies

$6g$ Hydrogen.

$24g$ requies

$xg$ Hydrogen.

$x=\cfrac{24\times 6}{28}=\cfrac{36}{7}=5.14$

$\therefore$

$5.14$ Hydrogen atoms required.

Give reasons:
Xenon does not form fluorides such as $Xe{ F }_{ 3 }$ and $Xe{ F }_{ 5 }$

All the filled orbitals of Xe have paired electrons. The promotion of 1, 2 or 3 electrons from the 5p filled orbitals to the 5d vacant orbitals will give rise to 2, 4 and 6 half-filled orbitals. Therefore, Xe can combine with even number of F-atoms but not odd.

In the manufacture of nitric acid by Ostwald's process, write
The chemical equation for the dissolution of $NO_2$ in water.

Nitrogen dioxide from secondary oxidation chamber is introduced into a special absorption tower. $NO_2$ gas passed through the tower and water is showered over it. By the absorption, nitric acid is obtained.

$3NO_2 + H_2O \rightarrow 2HNO_3 + NO$

Number of lone pairs on $Xe$ in $XeF_6$ is:

$Xe{F}_{6}$ ,

total number of valence electrons of

$Xe = 8$

$6$ electrons are shared with

$6$ Fluorine atoms,

Thus

$2$ electrons are left, i.e.,

$1$ lone pair.

Hence the correct answer is

$1$ lone pair.

Arrange following Ions in order of decreasing ionic radii ${ Li }^{ +2 },{ He }^{ + },{ Be }^{ +3 }$ ?

1351094_1175891_ans_42fcccace7c44e49b3e10738dcce3b2c.jpg

$Mg:$ s-block: : Nitrogen:_________

Nitrogen is a p-block (group 15) element.

What are noble gases? Give a reason why noble gases have stable electronic configuration.

Noble gases, also known as the inert gases, are the elements that belong to group 18 of the modern periodic table. Noble gases have a stable electronic configuration as their valence shell is complete.

Calculate the no of moles present in $2.044 \times 10^{23}$ number of Helium gas ?

$1$

$mole$ of helium gas has

$6.023\times 10^{23}$ molecules

$\implies 1$

$mole\rightarrow 6.023\times 10^{23}$

$molecules$

$\implies x\rightarrow 2.044\times 10^{23}$

$molecules$

$\implies x=\cfrac {2.044\times 10^{23}}{6.023\times 10^{23}}=\cfrac {1}{3}$

No. of moles of

$He=0.33$

Write the atomic number of the element present in the third period and seventeenth group of the periodic table.

The Element present in third period and seventeenth group of the periodic table is Chlorine

Atomic number of Chlorine is 17.

What is the action of ammonia on the ethyl chloride ?

When ammonia reacts with ethyl chloride, it undergoes ammonolysis reaction to form ethyl amine.

After the formation of ethyl amine (primary amine), it goes further to form secondary amine, tertiary amine, and quaternary ammonium

salt, respectively.

$CH_3-CH_2-Cl \xrightarrow {NH_3} C_2H_5-NH_2 \xrightarrow {C_2H_5-Cl} (C_2H_5)_2-NH\xrightarrow{C_2H_5-Cl} \\ (C_2H_5)_3-N\xrightarrow{C_2H_5-Cl}[C_2H_5]-NH_4^+-Cl^-$

The highest percentage of nitrogen is found in which among the following fertilizers among the given options?

Urea

Which of the following is a non-metal that remains liquid at room temperature?
Br, Cl, He, P

Bromine is a non metal that remains liquid at room temperature.

Why the elements of group $18$ are also known as noble gases?

The elements present in Group

$18$ have their valence shell orbitals completely filled and, therefore, react with a very few elements and that too only under special conditions. Therefore, they are known as noble gases.

Why S2 is bigger than O2

S2 is larger than O2 because S2 has more electrons than O2. ... S2 is larger than K+ because the decrease in electron repulsions that accompany addition of an electron causes the electron cloud to expand. S2 is larger than K+ because the two ions are isoelectronic and K+ has the larger Z and Zeff.

.Nitrogen in soil is an example for_______.

saturated

Name :

The most abundant element in the earth's crust.

Oxygen

How is Nitric Acid manufactured by Ostwald's Process?

Ostwald process to manufacture nitric acid-

Step

$1$ : Catalytic oxidation of Ammonia

A mixture of dry air and dry ammonia in the ratio of

$10 : 1$ by volume is compressed and then passed into a platinum gauze which acts as catalyst at about

$800 ℃$ .

$4 N{H}_{3} + 5 {O}_{2} \longrightarrow 4 NO + 6 {H}_{2}O + \text{Heat}$

Step

$2$ : Oxidation of nitric oxide

Nitric oxide combines with oxygen to form nitrogen dioxide at about 50°C.

$2 NO + {O}_{2} \longrightarrow 2 N{O}_{2}$

Step

$3$ : Absorption of nitrogen dioxide in water

The nitrogen dioxide and oxygen present in the air react with water to form nitric acid.

$4 N{O}_{2} + 2 {H}_{2}O + {O}_{2} \longrightarrow \underset{\text{Nitric acid}}{4 HN{O}_{3}}$

Nitric acid obtained is concentrated above

$50 \%$ . On further distillation,

$68 \%$ nitric acid is produced.

How $XeF_2$ and $XeF_4$ are prepared? What are their structure?

$Xe{F}_{2}$ and

$Xe{F}_{4}$ are obtained by a direct reaction between

$Xe$ and

${F}_{2}$ . The condition under which the reaction is carried out determines the product.

${Xe}_{\left( g \right)} + {{F}_{2}}_{\left( g \right)} \xrightarrow{673 K \; 1 \text{ bar}} {Xe{F}_{2}}_{\left( s \right)}$

${Xe}_{\left( g \right)} + 2 {{F}_{2}}_{\left( g \right)} \xrightarrow{873 K \; 7 \text{ bar}} {Xe{F}_{2}}_{\left( s \right)}$

Structure of

$Xe{F}_{2} \rightarrow$ The hybridisation of

$Xe{F}_{2}$ , is

$s{p}^{3}d$ with two bond pair and three lone pair of electrons. Thus the structure is trigonal bypyramidal.

Structure of

$Xe{F}_{4} \rightarrow$ In case of

$Xe{F}_{4}$ , the hybridisation is

$s{p}^{3}{d}^{2}$ with four bond pair and two lone pair of electrons. The two lone pairs will be opposite each other (to maintain symmetry), which makes for a square planar molecular geometry.

Why does fluorine shows anomalous behaviour?

Fluorine shows anomalous behaviour due to following reasons-

Small atomic size.
High electronegativity.
Low bond dissociation energy.
Absence of $d$ -orbitals in the valence shell.

What is the action of
conc nitnic acid on ethane

1313509_1475212_ans_2ee0e7b02b51477197a52153650dfd6e.JPG

State the use of aluminum

Aluminium is a silvery-white, lightweight metal. It is soft and malleable. Aluminium is used in a huge variety of products including cans, foils, kitchen utensils, window frames, beer kegs and aeroplane parts. This is because of its particular properties.

Given reasons for the following:
Dioxygen is a gas but sulphur a solid.

Oxygen is smaller in size as compared to sulphur due to which, it can effectively form

$p \pi - p \pi$ bonds and form

${O}_{2}$ molecule.

Also, the intermolecular forces in oxygen are weak van der Waal’s, which cause it to exist as a gas. On the other hand, sulphur does not form

${S}_{2}$ molecule but exists as a puckered structure held together by strong covalent bonds. Hence, it is solid.

Which of the following is a non metal that remains liquid at room temperature ?

The chemical element with the atomic number 35, Bromine is a non metal that remains liquid at room temperature. Mercury also remains liquid at room temperature but it is a metal. Bromine is the third lightest halogen.

Give the chemical name and formula of the substance formed as a brown ring in the test for nitrate radical.

The chemical name of the brown ring is Nitroso ferrous sulphate.
Formula:

$FeSO_4. NO$

What is the third most common gas found in the air we breathe ?

Argon

The most common gas people breathe from clean air is nitrogen. Air is a mixture of gases, and the air on Earth contains about 78 percent nitrogen and about 21 percent oxygen. Argon, carbon dioxide neon, helium, methane, krypton, hydrogen and xenon are in much smaller amounts

One method of producing $NH_{3}$ is by heating ammonium chloride, $NH_{4}Cl$ , with $CaO$ .
$2NH_{4} Cl + CaO \rightarrow 2NH_{3} + CaCl_{2} + H_{2}O$
Explain why the reaction of $NH_{4}Cl$ with $CaO$ produces ammonia.

Solution:-

$CaO$ is more basic than

$N{H}_{4}Cl$ and thus displaces ammonia

$\left( N{H}_{3} \right)$ from

${N{H}_{4}}^{+}$ .

What is the action of $NaOH$ on ammonium salts?

Ammonium chloride reacts with sodium hydroxide to produce ammonia, sodium chloride and water.

$NH_4Cl+NaOH\rightarrow NH_3+NaCl+H_2O$

Ammonia is prepared by the various method:

i) In the laboratory, it is prepared by heating ammonium chloride with sodium hydroxide or calcium hydroxide.

ii) Industrial manufacturing by Haber's process.

Answer the following:
Name two chalcogens

The chalcogens are the chemical elements in group 16 of the periodic table. This group is also known as the oxygen family.

Two name of chalcogens
1) Oxygen
2) Sulphur

Answer the following:
Which allotropic form of sulphur is more stable at room temperature?

The allotrope of sulphur that is more stable at room temperature is rhombic sulphur.

The following statement is true under certain conditions. Mention the condition in each case in a few words.
Hydrogen reacts with nitrogen to form ammonia.

At elevated temperature

$(500-550^o C)$ and high pressure

$(200\ atm)$ . in presence of a catalyst;

The reaction is:

$N_2+3H_2\xrightarrow{Fe} 2NH_3$

Name the element of group 17, which has the following properties:

Radioactive

$At$

Astatine is the only radioactive element in the group 17 (Halogen Family).

In the known interahalogen compounds $AB_n$ what is maximum value of n ?

When two different halogens reacts with each other interhalogen compounds are formed.

General formula:

$XY_n$

Where n= 1,3,5,7

X- Halogen which is less electronegative and larger in size

Y- Halogen which is more electronegative than

$X$ and smaller in size.

Maximum value of n is 7.

Answer the following:
(i) Write the general electronic configuration of halogens in the valence shell.

The halogens all have the general electron configuration

$ns^2np^5$

Answer the following:

Name the halogens.

These five non-metallic elements make up Group 17 of the periodic table and consist of: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At) known as halogens.

Answer the following:
Name four oxoacids of chlorine. Give their molecular formulae.

$HOCl$ (hypochlorous acid)

$HOClO$ (chlorous acid)

$HOClO_2$ (chloric acid)

$HOClO_3$ (perchloric acid)

Answer the following:

Name two interhalogens of $AB_3$ type.

1) Chlorine trifluoride

$ClF_3$

2) Bromine trifluoride

$BrF_3$

Complete the following reactions:
$XeF_6 + H_2O\rightarrow$

1676364_1728632_ans_ac1c906769034515873a7b5c1ffb3b5a.jpg

Name the noble gas which is not adsorbed in coconut charcoal

1672309_1728499_ans_5e028306b512485dadb66c55c033c408.jpg

Name the noble gas which is radioactive

1671534_1728496_ans_7267928c3940471abc428aed124b5213.jpg

Which one of the following does not exist?
(i) $XeOF_4$
(ii) $NeF_2$
(iii) $XeF_2$
(iv) $XeF_6$

1669372_1728510_ans_dae7a644eebe482a9eadc2dc336cd6e6.jpg

Complete the following reactions:
$XeF_6 + SiO_2\rightarrow$

1676348_1728621_ans_e50a22aef7e448d5b4d04fbad3b0b03c.jpg

Answer the following:

Name two poisonous gases of chlorine used in the warfare.

Phosgene

$( COCl_2)$ , Mustard gas

$C_4H_8Cl_2S$ these two gases of chlorine used in the warfare.

Complete the following reactions:
$XeF_6 + NH_3\rightarrow$

1676360_1728625_ans_dee4582ee25b4ce9ad967c3a5ddff1f5.jpg

Write short notes on:
(i) Interhalogen compounds.

An interhalogen compound is a molecule which contains two or more different halogen atoms (fluorine, chlorine, bromine, iodine, or astatine) and no atoms of elements from any other group.

Most interhalogen compounds known are binary (composed of only two distinct elements). Their formulae are generally XYn, where n = 1, 3, 5 or 7, and X is the less electronegative of the two halogens. The value of "n" in interhalogens is always odd, because of the odd valence of halogens. They are all prone to hydrolysis, and ionize to give rise to polyhalogen ions. Those formed with astatine have a very short half-life due to astatine being intensely radioactive.

The interhalogens of form XY have physical properties intermediate between those of the two parent halogens. The covalent bond between the two atoms has some ionic character, the less electronegative halogen, X, being oxidised and having a partial positive charge. All combinations of fluorine, chlorine, bromine, and iodine that have the above-mentioned general formula are known, but not all are stable. Some combinations of astatine with other halogens are not even known, and those that are known are highly unstable.

Answer the following:

Name the halogen which gives ozone with water.

Fluorine

$3F_2 +3H_2O \rightarrow 6HF +O_3$

Fluorine and water reaction is much different from other halogen reacts with water because of highest electronegativity of fluorine.

Write down the two compounds of Vth or $15th$ group elements which are covalent in vapour state but ionic in solid state.

Correct answer:-

$PCl_5$ and

$PBr_5$

Explanation:-

In gaseous and molten state

$PCl_5$ is neutral molecule with trigonal bipyramidal geometry.

In solid-state

$PCl_5$ is ionic which forms [PCl4]- anion and [PCl 6]+ cation that are tetrahedral and octahedral respectively.

Actually PBr5 is known to exist in solid-state,as highly reactive yellow solid.

Solid PBr5 exists in the form of PBr₄+ cation and Br- anion. In vapour phase it dissociates to form PBr₃ and Br₂.

Answer the following questions is a single digit integer.

How many noble gases are radioactive in nature?

Radon (Rn) and ununioctium (Uuo) these two elements are radioactive in nature.

What happens when water reacts with the following compounds?
Calcium cyanamide, $CaCN_2$

Calcium cyanamide on hydrolysis evolves

$NH_{3}(g)$ and also produces calcium carbonate.

$CaCN_{2}+3H_{2}O\rightarrow CaCO_{3}+2NH_{3}\uparrow$

Answer the following with relevant reason.
Why the group in which inert gases are accommodated was called zero group?

Inert gases do not show chemical reactivity under ordinary conditions due to possession of complete outermost shell, i.e., they show zero valency.

On account of zero valency, the group in which inert gases were placed was called zero group

Phosphorus has three allotropic forms- (A) White phosphorus (B) red phosphorus and (C) black phosphorus, Write the difference between white and red phosphorus on the basis of their structure and reactivity.

White phosphorus consists of

$P_4$ molecules, whereas the crystal structure of red phosphorus has a complicated network of bonding. White phosphorus has to be stored in water to prevent natural combustion, but red phosphorus is stable in air.
1883884_1729918_ans_cb49a0e9f9434dcf908c59b3f44fbdfa.jpg

1883884_1729918_ans_cb49a0e9f9434dcf908c59b3f44fbdfa.jpg

How will you bring about the following conversions?

Oxygen from nitre.

1572558_1733625_ans_f50203d04f2048e99c1af558f80cc509.jpg

How will you bring about the following conversions?

Ammonia from nitre.

On heating nitre with

$Zn$ in presence of aqueous

$NaOH$ , reduction of nitre to ammonia takes place.

$Zn+2NaOH\to Na_2ZnO_2+2[H]$

$KNO_3+8[H]\to KOH+2H_2O+NH_3$

Draw the structure of the following:
$XeF_{4}$ .

$XeF_{4}$ Square planar.
1635705_1777759_ans_af36f7d3e41c41c89ae979f4f8dd0a34.png

State reasons for the following:
$SF_{6}$ is kinetically an inert substance.

$SF_{6}, S$ atom is sterically protected by six

$F$ atoms and does not allow water molecules to attack the

$S$ atom. Further,

$F$ does not have

$d-orbitals$ to accept the electrons donated by

$H_{2}O$ molecules. Due to these reasons,

$SF_{6}$ is kinetically an inert substance.

Can $FCl_{3}$ exist? Comment.

No, because

$F$ atoms has no

$d-orbital$ and therefore it cannot expand its valance shell. Further, three big sized

$Cl$ atoms cannot be accommodated around a small

$F$ atom.

Complete the following equations:
$XeF_{4} + O_{2}F_{2} \rightarrow$

$XeF_{4} + O_{2}F_{2} \rightarrow XeF_{6} + O_{2}$ .

Why $He, Ne$ and $Ar$ called inert gas?

1691198_1773986_ans_0fe64497009c415d80bfaaea770cf40e.jpg

What are the two forms of oxygen found in the atmosphere?

Oxygen found in the atmosphere exist in 2 forms.

Elemental- this form of oxygen exists as di-oxygen molecule or $O_{2}$ . It forms 21% of the total air present on the earth. This form is present in the lower part of atmosphere where we live , it is non-poisonous and we inhale this form only. Plants also consume this form of oxygen.
Ozone- this form of oxygen is formed by the combination of 3 oxygen molecule, $O_{3}$ . It is present in the stratosphere region of earth's atmosphere and forms a protective layer around earth to protect us from the harmful U. V radiations coming from the sun. It is toxic and highly unstable, in the stratosphere also it keeps on breaking and forming in the presence of sunlight.

$\underset{(Elemental Oxygen)}{O_{2}}\rightarrow \underset{(ozone)}{O_{3}}$

Iodine form $I_{3}^{-}$ but $F_{2}$ does not form $F_{3}^{-}$ ions. Why?

$I_{2}$ , because of the presence of vacant

$d-orbitals$ , accepts electrons from

$I^{-}$ ions to form

$I_{3}^{-}$ ions but

$F_{2}$ because of the absence of

$d-orbitals$ does not accept electrons from

$F^{-}$ ions to form

$F_{3}^{-}$ ions.

Give the symbols for:
Most reactive non-metal of group $17$

1693292_1773981_ans_df3993d225744e1a81462adc3920d4d4.jpg

Account for the following:
$PF_{5}$ is known but $NF_{5}$ is not known.

$P$ has vacant

$3d-orbitals$ in its valence shell while

$N$ does not have. As a result,

$P$ can form additional bonds to give

$PF_{5}$ while

$N$ cannot extend its covalency beyond three and hence it forms only

$NF_{3}$ but not

$NF_{5}$ .

Write the balanced chemical equations for the following reactions and identify the type of reaction in each case.
(a) Nitrogen gas is treated with hydrogen gas in the presence of a catalyst at 773K to form ammonia gas.

$N_{2(g)}+3 H_{2(g)} \frac{\text {Catalyst/773K}}{} 2 N H_{3(g)}$

This is a combination reaction.

Account for the following:
Both $NO$ and $ClO_{2}$ are odd electron species but $NO$ dimerises while $ClO_{2}$ does not.

$NO$ , the odd electron on

$N$ by only one

$O-atom$ but in

$ClO_{2}$ , the odd electron on

$Cl$ is attracted by two

$O-atoms$ . Thus, the odd electron on

$N$ in

$NO$ is localised while the odd electron on

$Cl$ in

$ClO_{2}$ is delocalised. Consequently,

$NO$ has a tendency to dimerise but

$ClO_{2}$ does not.

Explain the following observations:
Helium forms no real chemical compound.

This is because the valence shell orbital of helium is completely filled

$(1s^{2})$ and it has high ionisation enthalpy and more positive electron gain enthalpy.

Answer the following question:
What is the structural difference between white phosphorus and red phosphorus.

White phosphorus consists of discrete tetrahedral

$P_{4}$ molecule with six

$P-P$ covalent bonds.

Red phosphorus has polymeric structure in which

$P_{4}$ tetrahedra are linked together through

$P-P$ covalent bond to form chain.

First member of each group of representative elements (i.e., s and p-block elements) shows anomalous behavior. Illustrate with two examples.

Anomalous Properties of Second Period Elements: Their anomalous behavior is attributed to their small size, large charge/radius ratio, high electronegativity and non-availability of d-orbitals in their valence shell. The first member of each group of p-Block elements displays greater ability to form

$p_\pi - p_\pi$ multiple bonds to itself (e.g.,

$C=C, \ C=C, \ O=O, \ N=N$ ) and to other second period elements (e.g.,

$C=O, \ C=N, \ N=O$ compared to subsequent members of the group.

Name:

Two substances from which oxygen can be obtained at a large scale.

Air, water.

In electron dot structure, the valence shell electrons are represented by crosses or dots.
(a) the atomic number of chlorine isWrite its electronic configuration
(b) Draw the electron dot structure of chlorine molecule.

(a) Electronic configuration of chlorine: 2.8,7
(b) Electron dot structure of chlorine molecule:
1651427_1791457_ans_517ba686eaea42a18718f50e1c77fd12.png

1651427_1791457_ans_517ba686eaea42a18718f50e1c77fd12.png

Give reasons for the following:
Neon is generally used for warning signals.

Neon lights are visible from long distances even in fog and mist and hence neon is generally used for warning signals.

How would you account for the following:
Fluorine never acts as the central atom in polyatomic interhalogen compounds.

Fluorine never acts as the central atom in polyatomic interhalogen compounds since it is the most electronegative element of the among the halogens.

Give balanced equations to obtain oxygen from:

Lead dioxide

$2 PbO_2$

$\rightarrow$

$2PbO \,\, + \,\, O_2 \uparrow$

(Chocolate brown)

Name the type of elements , which have their
One electron short of octet - ...................

One electron short of octet -

$\textbf {Halogens }$

An element X belong to $4^{th}$ period and $17^{th}$ group , state name of the element.

The name of the element is

$\textbf {Bromine.}$

Fluorine , chlorine and Bromine are put in one group of their similar properties .
What is the common name of this group or family.

They belong to

$\textbf {family of halogens }$ .

Name two elements in each case :
Halogens

2 examples are : Chlorine and bromine

This question refers to the elements of the periodic table with atomic number from $3$ to $18$ . Some of the elements are shown by letters , but the letters are not the usual symbols of the elements.

$3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
A B C D E F G H
$11$ $12$ $13$ $14$ $15$ $16$ $17$ $18$
I J K L M N O P

Which of these is a halogen ?

Atomic number

$7$ and

$11$ are Halogens -

$G$ and

$O$

Which element has :
Two shells, both of which are completely filled with electrons ?

Neon

An element X belong to $4^{th}$ period and $17^{th}$ group , name the family to which it belongs.

Bromine belongs to the

$\textbf {halogen family.}$

Name the type of elements , which have their
Outermost shell complete ...............

$\textbf {Noble gases}$ are the chemical elements in group

$18$ of the periodic table. They are the most stable due to having the maximum number of valence electrons their outer shell can hold. Therefore, they rarely react with other elements since they are already stable.

Name two elements in each case :
Inert gas

2 examples are : Neon and Argon

Name :
An alkali metal in period $3$ and halogen in period $2$ .

Sodium is alkali metal and fluorine is halogen.

Name:
a nitride of a divalent metal which reacts with warm water liberating ammonia.

Magnesium nitride =

$Mg_3N_2$ reacts with warm water liberating ammonia.

Ammonia is used in the Ostwald process,
1) Name the catalyst used in the process.
2) Name the oxidizing agent used in this process.

1) The catalyst used in the process is Platinum.
2) Oxygen is used as oxidising agent in Ostwald Process.

Ammonia is used in the Ostwald process,
What is the ratio of ammonia and air taken in this process ?

Ratio of ammonia and air is

$1 : 10$

Ammonia is used in the Ostwald process,
Name the oxidizing agent used in this process.

The oxidizing agent used in the process is oxygen.

Give balanced equations for the following conversation:
A nitride of a trivalent metal to ammonia.

$AlN+3H_2O \rightarrow Al(OH)_3+NH_3$

Ammonia is used in the Ostwald process,
Give the sources of reactants used in this process.

Dry air free from carbon dioxide and dry ammonia from Haber's process.

Name :
The noble gas with $3$ shells .

Argon

Correct the following:
Ammonium salts on heating decompose to give ammonia.

Ammonium salts when heated with caustic alkali decompose to give ammonia.

Complete the following equation.
$Mg_3N_2 + 6H_2O \rightarrow$

$Mg_3N_2 + 6H_2O \rightarrow 3Mg(OH)_2 + 2NH_3$

Write the equations for the following reactions which result in the formation of ammonia.
A mixture of ammonium chloride and slaked lime is heated.

$2NH_4Cl + Ca(OH)_2 \overset{\Delta}{\longrightarrow} CaCl_2 + 2H_2O + 2NH_3$

Write a balanced chemical equation for the lab preparation of ammonia.

Lab preparation of ammonia:

$2NH_4Cl + Ca(OH)_2 \rightarrow CaCl_2 + 2H_2O + 2NH_3$

Ammonia is used in the Ostwald process,
Why is quartz used in this process ?

Quartz is acid-resistant and when packed in layers helps in dissolving nitrogen dioxide uniformly in water.

Write the equations for the following reactions which result in the formation of ammonia.
Aluminium nitride and water.

$AlN + 3H_2O \overset{\Delta}{\longrightarrow} Al(OH)_3 + NH_3$

Why is ammonia not collected over water ?

Ammonia is not collected over water because it is highly soluble in water.

Write equation for the following:
Aluminium nitride and water.

Equation:

$AlN + 3H_2O \rightarrow Al(OH)_3 + NH_3$

Write the equation for the formation ammonia by the action of water on magnesium nitride.

$Mg_3N_2 + 6H_2O \rightarrow 3Mg (OH)_2 + 2NH_3$

Which compound is normally used as a drying agent for ammonia ?

Quicklime is used as a drying agent for ammonia.

Ammonia gas can be prepared by warming an ammonium salt with caustic alkali. Give two equations.

Ammonia gas can be prepared by warming an ammonium salt with caustic alkali. The two equations are:

$(NH_4)_2SO_4 + 2NaOH \overset{\Delta}{\longrightarrow} Na_2SO_4 + 2H_2O + 2NH_3$

$(NH_4)_2SO_4 + 2KOH \overset{\Delta}{\longrightarrow} K_2SO_4 + 2H_2O + 2NH_3$

How is ammonia collected ?

Ammonia gas is collected in inverted gas jars by the downward displacement of air.

How will you prepare the following from nitric acid?
Sodium nitrate

Sodium nitrate:

$NaOH + HNO_3 \longrightarrow NaNO_3 + H_2O$
Sodium hydroxide reacts with nitric acid to form sodium nitrate.

Ammonia cannot be collected over water. Give reason.

Ammonia is highly soluble in water and therefore it cannot be collected over water.

How is ammonia dried and collected in the laboratory ?

The ammonia gas is dried by passing through a drying tower containing lumps of quicklime

(CaO)(CaO)

Correct the following, if required:
Constant boiling nitric acid contains $80\%$ nitric acid by weight.

Constant boiling nitric acid contains

$68\%$ nitric acid by weight.

Give reasons for the following:
In the laboratory preparation of nitric acid, the mixture of concentrated sulphuric acid and sodium nitrate should not be heated very strongly above $200^\circ \ C$ .

The temperature of the mixture of concentrated sulphuric acid and sodium nitrate should not exceed

$200^\circ$ because sodium sulphate formed at higher temperature forms a hard crust which sticks to the walls of the retort and is difficult to remove. At higher temperature nitric acid may also decompose.

$NaNO_3 + NaHSO_4 \overset{>200^\circ}{\longrightarrow} Na_2SO_4 + HNO_3$

Give reasons:
Ammonium nitrate is not used in the preparation of ammonia.

Ammonium nitrate is not used in the preparation of ammonia as it is explosive in nature and it decomposes forming nitrous oxide and water vapours.

A substance 'A' was heated with slaked lime and a gas 'B' with a pungent smell was obtained. Name the substances A and B and give a balanced equation.

The substance A is ammonium chloride and 'B' is Ammonia.
Reaction:

$2NH_4Cl + Ca(OH)_2 \rightarrow CaCl_2 + 2H_2O + 2NH_3$

Explain with a diagram the preparation of aqueous ammonia.

Preparation of Aqueous Ammonia: An aqueous solution of ammonia is prepared by dissolving ammonia in water. The rate of dissolution of ammonia in water is very high; therefore, the back suction of water is possible. To avoid this, a funnel is attached to the outer end of the delivery tube with rubber tubing.

Procedure: Water is taken in a container and only a small portion of the mouth of the funnel is dipped in water.

As ammonia dissolves in water at a higher rate than its production in the flask, the pressure in the funnel above water level decreases for a moment and water rushes into the funnel. As a result, the rim of the funnel loses its contact with water. Since ammonia produced pushes the water down, the funnel comes in contact with water again. In this way, ammonia dissolves in water without a back suction of water.

1712621_1808247_ans_4f272de8586f448ab770af66aeb626a3.png

In the preparation of nitric acid from $KNO_3$ concentrated hydrochloric acid is not used in place of concentrated sulphuric acid. Explain why?

Concentrated hydrochloric acid cannot replace Conc. Sulphuric acid for the preparation of nitric acid because hydrochloric acid is volatile acid and hence nitric acid vapors will carry

$HCl$ vapors.

Give reasons:
Conc $H_2SO_4$ is a good drying agent, yet it is not used to dry $NH_3.$

Conc.

$H_2SO_4$ is not used to dry ammonia, as ammonia being basic reacts with them.

$2NH_3 + H_2SO_4 \rightarrow (NH_4)_2SO_4$

The figure given below illustrates the apparatus used in the laboratory preparation of nitric acid.
Write the equation for the reaction in which copper is oxidized by concentrated nitric acid

Copper is oxidized by concentrated nitric acid:

$Cu + 4HNO_3 \longrightarrow Cu(NO_3)_2+ 2H_2O + 2NO_2$

Name the minerals of chlorine.

The most common minerals of chlorine are Halite (rock salt), sylvite, chlorapatite, etc.

How will you prepare the following from nitric acid?
Magnesium nitrate

Magnesium nitrate:

$Mg + 2HNO_3 \longrightarrow Mg (NO_3)_2 + H_2$
Magnesium with dil. nitric acid to form magnesium nitrate.

What are the three allotropic forms of phosphorous.

White phosphorous
Red phosphorous
Black phosphorous.

The figure given above illustrates the apparatus used in the laboratory preparation of nitric acid.
Name A (a liquid), B (a solid) and C (a liquid). ( Do not give the formulae)

A = Conc. Sulphuric acid
B = potassium nitrate
C = nitric acid

Explain why:
Nitric acid is kept in a reagent bottle for a long time.

Nitric acid is kept in reagent bottle because nitric acid is a highly fuming liquid; it spreads in air and is highly corrosive.

The figure given below illustrates the apparatus used in the laboratory preparation of nitric acid.
Write an equation to show how nitric acid undergoes decomposition.

Nitric acid undergoes decomposition as follows:

$4HNO_3 \overset{\Delta}{\longrightarrow} 4NO_2 + 2H_2O + O_2$

How will you prepare the following from nitric acid?
Copper nitrate

Copper nitrate:

$CuO + 2HNO_3 \longrightarrow Cu(NO_3)_2 + H_2O$

Name the common element present in bleaching powder and common salt ?

Chlorine is the common element present in bleaching powder and common salt.

Name the compound of chlorine which is disinfectant.

Sodium chloride is the compound of chlorine which is disinfectant.

Arrange the apparatus as shown in figure
What do you observe ?

Water in the beaker lifts up in the flask which is filled with ammonia.

Write the equation of the reaction for the formation of ammonia.

Reaction for preparation of Ammonia:

$N_2+3H_2 \to 2 NH_3$

Name the industrial production of ammonia.

Haber process is the process used for preparation of ammonia.

In the manufacture of ammonia, the reaction in which direction results in the decrease in the number of molecules is

In the manufacture of ammonia, the reaction in which direction results in the decrease in the number of molecules is Forward reaction.

What is covalency of chlorine atom in second excited state ?

covelency is 5

Discuss the conditions required in the Haber process for the manufacture of ammonia.

1931158_1873105_ans_0da8eb371a854af6a6a505c747c7ffad.jpg

What is the structure of nitric acid ?

1931203_1873143_ans_5bb74a911f02412cb29c93962e07cea2.jpg

How is nitric acid manufactured from ammonia ?

1931168_1873120_ans_70fb28b5a4fa4bd881a3a1e5b7b8e60b.jpg

Consider following compounds A to E.
(A) $XeF_{n}$ (B) $XeF_{(n + 1)}^{+}$ (C) $XeF_{(n + 1)}^{-}$ (D) $XeF_{(n + 2)}$ (E) $XeF_{(n + 4)}^{2-}$
If value of n is 4, then calculate value of "p + q" here, 'p' is total number of bond pair and 'q' is total number of lone pair on central atoms of compound A to E.

	b.p.	l.p.
(A) $XeF_{4}$	$4$	$2$
(B) $XeF_{5}^{+}$	$5$	$1$
(C) $XeF_{5}^{-}$	$5$	$2$
(D) $XeF_{6}$	$6$	$1$
(E) $XeF_{8}^{2-}$	$8$	$1$

So, the value of p+q = 35

Write balanced equation(s) for the manufacture of nitric acid by the oxidation of ammonia.

1931170_1873121_ans_40d1ec954d04404cb48e7f28d38e9f1f.jpg

Match List-I with List-II.

$HNO_{2}$ can show tautomerism and hybridisation remains the same.
(B)

$SOF_{2}+2H_{2}O\rightarrow 2HF+H_{2}SO_{3}$
* Non - redox reaction, sulphurous acid undergoes tautomerism, hybridisation remains the same

$(sp^{3})$ .
* HF can react with

$SiO_{2}$ (glass)

$SiO_{2} + 4HF \rightarrow SiF_{4} + 2H_{2}O$
(C)

$XeF_{4} + H_{2}O \rightarrow Xe + O_{2} + XeO_{3} + HF$
Redox reaction and HF can react with

$SiO_{2}$
(D)

$ClF_{6} + 3H_{2}O \rightarrow HClO_{3}^{+5}+5HF$
* Non - redox reaction
* HF reacts with glass and

$HClO_{3}$ can undergo tautomerism.

Find the sum of the total number of $P - \hat{P} - P$ angle and $P - P$ sides in $P_4$ molecule.

$P_4$ molecule has pyramidal geometry. It has

$6\ P-P$ sides. Therefore, the number of

$P-P-P$ angles is 12. Hence, the sum of

$P - \hat{P} - P$ angle and

$P - P$ sides in a

$P_4$ molecule is

$6+12=18$ .

All the compounds listed in column-I react with water. Match the result of the respective reactions with appropriate options listed in column-II.

(A)

$3XeF_4 + 6H_2O \rightarrow XeO_3(sp^3) + 2Xe +\frac {3}{2} O_2 + 12HF$ ; HF reacts with glass
(B)

$2H_2O + 2F_2\rightarrow 4HF + O_2$ ; HF reacts with glass
(C)

$PCl_5 + 4H_2O \rightarrow H_3PO_4 (sp^3) + 5HCl$
(D)

$VCl_5 + H_2O\rightarrow VOCl_3 (sp^3) + 2HCl$

$4NH_{3} (g) + 5O_{2}(g) \rightarrow 4NO(g) + 6H_{2}O(l)$
$2NO(g) + O_{2}(g) \rightarrow 2NO_{2}(g)$
$2NO_{2}(g) + H_{2}O(l)\rightarrow HNO_{3}(aq) + HNO_{2}(aq)$
Consider the reactions of the Ostwald Process for the production of nitric acid above.
The first reactions have $50$ % yields and the last reaction has $25$ % yield.
Mass of $NH_{3}$ would be needed to produce $126\ g$ of $HNO_{3}$ is __________ gm.

1497176_533368_ans_2373b6b4ca5744708aec40451cbc5270.jpg

Explain the following giving an appropriate reason in each case.
(i) $O_2$ and $F_2$ both stabilize higher oxidation states of metals but $O_2$ exceeds $F_2$ in doing so.
(ii) Structures of xenon fluorides cannot be explained by valence bond approach.

(i)

$O_2,F_2$ both will stabilize the higher oxidation states. But the higher oxidation state of metal with

$O_2$ is more stable. Because oxygen will gain 2 electrons from metal atom but the fluorine gains only 1 electron leading to the formation of

$O^{2-}, F^{-}$ . The bond between metal and non-metal will be strong when the metal is able to lose more electrons to non metal so the higher oxidation state stabilizes the compound.

II) The compounds of xenon fluorides like

$XeF_2,XeF_4,XeF_6$ can not be explained using valence band theory because in valence bond theory we take valence electrons into consideration but in compounds of xenon we have lone pair electrons which affect the shape of a molecule. So, the compounds of xenon are explained by valence shell electron pair repulsion theory.

With what neutral molecule is $ClO^{-}$ isoelectronic? Is that molecule a Lewis base?

$\displaystyle ClO^-$ is isoelectronic with

$ClF$ . It is a Lewis base.

Arrange the following in order of property indicated for each set:
a. $F_{2}, Cl_{2}, Br_{2}, I_{2}$ - increasing bond dissociation enthalpy.
b. $HF, HCl, HBr, HI$ - increasing acid strength.
c. $NH_{3}, PH_{3}, AsH_{3}, SbH_{3}, BiH_{3}$ - increasing base strength.

(i)

$\displaystyle I_2 < F_2 < Br_2 < Cl_2$ The electron affinity of Chlorine is maximum in the periodic table and so the bond dissociation enthalpy. Flourine has lower bond dissociation enthalpy than

$Br_2$ and

$Cl_2$ . Due to small size electronic repulsion is very high.

$I_2$ has lowest bond dissociation enthalpy due to quite larger size it is easiest to break the bond.

(ii)

$\displaystyle HF < HCl < HBr < HI \Rightarrow$ Acidic strength of Halogen acids increases down the group.

(iii)

$\displaystyle BiH_3 < SbH_3 < AsH_3 < PH_3 < NH_3\Rightarrow$ Basic strength decreases down the group because as we go down the group the size of the atom and thus the electron density decreases. These compounds are lewis base having 1 lone pair on the central atoms. As the electron density decrease the tendency to donate electron pair decreases.

In an experiment, the solubility of iodine in diethyl ether, n-hexane, Carbon Tetrachloride and toluene was measured. The solubilities were: 337g/kg, 182g/kg,19 g/kg and 13 g/kg. Correlate the solubilities with the solvents
Solvent Solubility Solvent Solubility
Carbon tetrachloride A n-Hexane B
Diethyl ether C Toluene D
Find the value of A+B.

Solvent	Solubility	Solvent	Solubility
Carbon tetrachloride	19	n-Hexane	13
Diethyl ether	337	Toluene	182

Iodine is highly soluble in nonpolar organic solvents like diethyl ether, ethanol, toluene but least soluble in carbon tetrachloride and hexane because of weak induced dipole forces.

How to do lab preparation of ammonia using an ammonium salt?

Ammonia is prepared from ammonium chloride by using calcium hydroxide.

$2NH_4Cl + Ca(OH)_2 \rightarrow CaCl_2 + 2NH_3 + 2H_2O$

Give reasons for the following:
(i) $Zn^{+2}$ salts are while but $Cu^{2+}$ salts are blue in colour.
(ii) Fluorine gives only one oxide but chlorine gives a series of oxides.

(i) Zinc and copper are transition metals and their ions are generally coloured due to d-d transition of unpaired electron.
But in case of

$Zn^{2+}3d$ is completely filled and no unpaired electrons are available for transition. So light falling on these ions gets completely transmitted and their salts appear white. How ever ion

$Cu^{2+}3d$ has

$9$ electrons. The unpaired electron absorbs particular wavelengths in visible region of light and the transmitted light shows the complementary colour 'blue'.
(ii) Fluorine has only two orbits. In

$2$ nd orbit it has

$s^2p^5$ configuration with no vacant 'd' orbitals. So it can not form more than one oxide i.e.,

$OF_2$ .
Chlorine, on the other hand, has

$3$ orbits in its atoms and

$3d$ is lying vacant in it. Therefore it can show variable covalency and gives a series of oxides. Like

$Cl_2O, ClO_2$ .

(a) Name two oxoacids of sulphur.
(b) (i) How will you manufacture ammonia by Haber process?
(ii) Write any two uses of inert gases.

i) Oxoacids of sulfur are:

Sulfurous acid $H_2SO_3$
Sulfuric acid $H_2SO_4$

b) i) Ammonia is manufactured using Haber's process by taking $N_2,H_2$ in $1:3$ proportions. Both are reacted in a tank in presence of $Fe,Mo$ which are catalyst and promoter respectively.

$N_2+3H_2\rightarrow 2NH_3$

ii) Helium is much less dense (lighter) than air and is used in balloons and blimps. Because of its inertness, it doesn’t burn in air unlike hydrogen which was formally used in large balloons

Neon is used in the familiar ‘neon sign” used in advertisement.

Argon, like all the noble gases is chemically inert. It is used in filament bulbs because the metal filament will not burn in argon

Describe with chemical equation the Laboratory method for the preparation of ammonia. Write its reaction with the following:
(i) Oxygen in presence of platinum at ${800}^{o}C$ .
(ii) Red hot copper oxide.

Laboratory method for the preparation of ammonia:
Ammonium chloride is heated with calcium hydroxide.

$\displaystyle 2NH_4Cl+Ca(OH)_2 \xrightarrow {\Delta } CaCl_2 +2NH_3 + 2H_2O$
Moist ammonia gas is dried over CaO (quik lime).
The reactions of ammonia with:
(i) Oxygen in presence of platinum at

${800}^{o}C$ .

$\displaystyle 4NH_3+5O_2 \xrightarrow [{800}^{o}C]{Pt}4NO+6H_2O$
(ii) Red hot copper oxide.

$\displaystyle 2NH_3+3CuO \xrightarrow {\Delta} 3Cu+3H_2O+N_2$

How will you obtain the following (Give only chemical equations)?
(i) ${ N }_{ 2 }$ from ${ NH }_{ 3 }$
(ii) ${ NH }_{ 3 }$ from ${ NH }_{ 4 }Cl$

(i)

${ N }_{ 2 }$ from

${ NH }_{ 3 }$ by oxidation:

$\displaystyle 8NH_3+3Cl_2 \rightarrow 6NH_4Cl+N_2$

$\displaystyle 2NH_3+3CuO \xrightarrow {\text {heat}} 3Cu+N_2+3H_2O$

(ii)

${ NH }_{ 3 }$ from

${ NH }_{ 4 }Cl$

$\displaystyle 2NH_4Cl+Ca(OH)_2 \rightarrow CaCl_2+2H_2O+2NH_3 \uparrow$

Write only the types of hybridisation of central atom present in $XeF_{2}$ and $XeF_{4}$ .

$XeF_{2}$ , 2 bond pairs and 3 lone pairs of electrons are present around central Xe atom. The types of hybridisation is

$sp^3d$ .
In

$XeF_{4}$ , 4 bond pairs and 2 lone pairs of electrons are present around central Xe atom. The types of hybridisation is

$d^2sp^3$ .

Describe with suitable diagram the Deacon process of manufacture of chlorine. Write its reaction with ammonia.

Deacon process is a method of obtaining chlorine gas by passing oxygen/air and hydrogen chloride gas over a heated catalyst (such as copper chloride).

It is a two step process:

1. At elevated temperature (about 500 K),

$HCl$ is added to the vessel containing the transition metal catalyst as metal oxide. The metal oxide gets converted to metal chloride with the elimination of water.

2. Upon passing oxygen over the metal chloride (at temperature atleast 573 K),

$Cl_2$ gas evolves and reconverts the metal chloride to its oxide.

Overall reaction:

$4HCl+{ O }_{ 2 }\overset { catalyst }{ \rightarrow } 2{ H }_{ 2 }O+2{ Cl }_{ 2 }$

Various catalysts can be used such as:

$MnO_2, Co_2O_3, NiO$ etc.

Reaction of chlorine with ammonia:

1. excess of ammonia:

$3{ Cl }_{ 2 }+8N{ H }_{ 3 }\rightarrow 6N{ H }_{ 4 }Cl+{ N }_{ 2 }\uparrow$

2. Excess of chlorine:

$3{ Cl }_{ 2 }+N{ H }_{ 3 }\rightarrow \underset { explosive }{ N{ Cl }_{ 3 } } +3HCl$

$40%$ of a mixture of $0.2 \,mol$ of $N_2$ and $0.6 \,mol$ of $H_2$ reacts to give $NH_3$ according to the equation:
$N_2(g) + 3H_2(g) \rightleftharpoons 2NH_3(g)$

1342474_1136467_ans_1bfa6199f23542bb9679ac372d0d66f3.jpg

What happens to the following properties of group 15 hydrides as we move down the group?
Basic Character
Thermal stability
Reducing nature
Dipole moment
Bond angle

$)1)$ Basic character decreases from

${ NH }_{ 3 }$ to

${ BiH }_{ 3 }$ because as the size of central atom increases, electron density on central atom decreases and hence its ability due donate pair of electron decreases and thus its basic character decreases from

${ NH }_{ 3 }$ to

${ BiH }_{ 3 }$ .

$(2)$ Thermal stability decreases

$\rightarrow$ Thermal stability

$\alpha \dfrac { 1 }{ sizes }$ so as size of central atom increases, so stability decreases.

$(3)$ Reducing nature increases

$\rightarrow$ As the stability of hydride decreases down the group its reducing power increases.

$(4)$ Dipole moment decreases

$\rightarrow$ As the electronegativity of the central atom decreases down the group, the dipole moment of hydrides of these elements decreases.

$95)$ Bond angle decreases

$\rightarrow$ The hydrides of these elements are pyramidal in shape with a lone pair of electrons in one of the orbitals. On moving down the group the bond angles gradually decrease due to a decrease in bond pair-bond pair repulsion.

Write the equations involved in the manufacture of nitric acid by Ostwald's process by maintaining reaction conditions.

The equations involved in the manufacture of nitric acid by Ostwald's process are given below.

$4NH_3{(g)}+5O_2{(g)}\xrightarrow[\text {500K. 9bar}]{\text {Pt/Rh gauge catalyst }} 4NO{(g)}+6H_2O{(g)}$

$2NO{(g)}+O_2{(g)} \rightleftharpoons 2NO_2{(g)}$

$3NO_2{(g)}+H_2O{(g)}\rightarrow 2HNO_3{(l)}+NO{(g)}$ .

$34$ gm of a mixture containing ${ N }_{ 2 }$ and ${ H }_{ 2 }$ in $1:3$ by mole is partially converted into ${ NH }_{ 3 }$ . Calculate the vapour density of the mixture (containing remaining ${ N }_{ 2 },{ H }_{ 2 }$ and ${ NH }_{ 3 }$ formed) after reaction if it has been found that the ${ NH }_{ 3 }$ formed required $0.5$ moles of ${ H }_{ 3 }{ PO }_{ 4 }$ for complete neutralization.

$N_2+3H_2 \rightleftharpoons 2NH_3$

Let mass of

$N_2$ be

$x$

$g$

Then mass of

$H_2$ will be

$(34-x)g$

moles of

$N_2= \cfrac {x}{28}$ , moles of

$H_2= \cfrac {34-x}{2}$

as their molar ratio is

$1:3$

So,

$\cfrac {\cfrac {x}{28}}{\cfrac {(34-x)}{2}}= \cfrac {1}{3} \Rightarrow \cfrac {6x}{28}=34-x$

$\Rightarrow 6x= 34 \times 28- 28x$

$\Rightarrow 34x= 34 \times 28$

$\Rightarrow x=28 \Rightarrow$ Mass of

$N_2$

$\Rightarrow 34-x= 34-28=6\longrightarrow$ Mass of

$H_2$

Number of moles of

$N_2= \cfrac {28}{28}=1$

Number of moles of

$H_2= \cfrac {6}{2}=3$

$\underset {1}{N_2}+\underset {3}{3H_2} \rightleftharpoons \underset {-}{2NH_3}$

$1-y$

$3-3y$

$2y$

$NH_3$ required

$0.5$ moles of

$H_3PO_4$

So,

$\underset {(H_3PO_4)}{n \times n_f}= \underset {(NH_3)}{n \times n_f}$

(as

$n_f$ for

$H_3PO_4$ is

$3$ )

$\Rightarrow 0.5 \times 3= n \times 1$

$n=1.5$ moles of

$NH_3$

Thus

$2y= 1.5$

$\Rightarrow y= \cfrac {1.5}{2}= 0.75$ moles of

$NH_3$

Number of moles remain in solution Mass remain in solution

$N_2 \longrightarrow 1-0.75= 0.25$

$0.25 \times 28=7g$

$H_2 \longrightarrow 3-3\times 0.75= 0.75$

$0.75 \times 2= 1.5g$

$NH_3 \longrightarrow 2 \times 0.75= 1.5$

$1.5 \times 31= 46.5g$

Vapour density=

$\cfrac {Effective\quad Molar\quad mass\quad (EMM)}{2}$

$\Rightarrow EMM= \cfrac {m_1+m_2+m_3}{n_1+n_2+n_3}=\cfrac {7+1.5+46.5}{0.25+0.75+1.5}$

$\Rightarrow EMM=22$

Vapour density of mixture=

$\cfrac {22}{2}=11$ .

In the manufacture of ammonia by Haber's process, write the flow chart and chemical equations with optimum conditions.

In the manufacture of ammonia by Haber's process, the flow chart is as shown.

The chemical equation is

$N_2+3H_2\rightleftharpoons 2NH_3$

The optimum conditions are temperature

$=700$ K and Pressure

$=200$ atm.

Answer the following question:
a. What is the basicity of $H_{3}PO_{3}$ and why?
b. Why does fluorine not play the role of a central atom in interhalogen compound?
c. Why do noble gases have very low boiling points?

(a) Two, as the structure of

$H_{3}PO_{3}$ has two

$P-OH$ bonds.

(b) This is due to smaller size and absence of

$d$ orbitals in the valence shell of fluorine.

(c) Noble gases being monoatomic gases have no interatomic forces except weak dispersion forces, therefore they have low boiling points.

980558_1077948_ans_c32321574eb44654a5f9de87c64586ed.png

Write the formula of the compound of phosphorous which is obtained when $conc. HNO_{3}$ oxidises $P_{4}$ .

1657254_1406176_ans_36289c39a87843b8b42dd7b94b6795d8.jpg

How is ammonia manufactured by Haber's process ? Explain.

On an industrial scale, ammonia is prepared by Haber’s process. The constituents of ammonia

${N}_{2}$ and

${H}_{2}$ combine in a ratio of

$1 : 3$ .

${N}_{2} + 3 {H}_{2} \rightleftharpoons 2N{H}_{3}$

The reaction proceeds in the forward direction with a remarkable decrease in volume and thus the reaction is exothermic. In accordance with Le Chatelier’s principle, high pressure would favour the formation of ammonia. The optimum conditions for the production of ammonia are a pressure of approx

$200 \; atm$ , a temperature of approx

$700 \; K$ and the use of a catalyst such as iron oxide with small amounts of

${K}_{2}O$ and

${Al}_{2}{O}_{3}$ to increase the rate of attainment of equilibrium.

1188163_1469228_ans_ce9c5438f70c41b19a6e5911a4ab8d70.png

Describe the manufacture of nitric acid Ostwald's process.

1462500_1597583_ans_57dc1fb64cee4b42b4ba7ee664a687be.jpg

Why fluorine is a stronger oxidizing agent than chlorine?

Fluorine is more electronegative than chlorine therefore it can attract a share pair of electron more easily and strongly than chlorine. Thus, it can easily accept the pair of electrons and undergoes reduction. Thus it is a strong oxidising agent than chlorine.

What is the action of water on the following?
Calcium cyanamide

Calcium cyanamide,

$CaCN_2$ , reacts with water to form calcium carbonate and ammonia;

$CaCN_2 + 3H_2O \rightarrow CaCO_3 + 2NH_3$

What is the action of water on the following?
Calcium nitride

Calcium nitride reacts with water or even the moisture in air to give ammonia and calcium hydroxide

$Ca_3N_2 + 6H_2O \rightarrow 3Ca(OH)_2 + 2NH_3$

Why fluorine shows anomalous behaviour as compared to other halogens?

Fluorine differs from rest of the members of its group because of its small size, high electro negativity and non availability of d orbitals in the valence shell.

Which gases are evolved when $Mg_3N_2$ reacts with water?

1566841_1726405_ans_264c59c1a2d74bbfbbc8cc6532b84a7d.JPG

Describe the action of heat on ammonium chloride.

1621655_1728461_ans_992926ac06284972808242847063342d.jpg

Describe the principle of manufacture with conditions of the following compounds:
Ammonia by Haber process.

On an industrial scale, ammonia is prepared by Haber’s process. The constituents of ammonia

$N_2$ and

$H_2$ combine in a ratio of

1 : 3

N_2

200 a t m

, a temperature of approx

700 K

and the use of a catalyst such as iron oxide with small amounts of

$K_2O$ and

$Al_2O_3$

to increase the rate of attainment of equilibrium.

How will you prepare ammonia from calcium carbide?

1671541_1728524_ans_415a15745ec64fa4a4282f9bbe9d15c2.jpg

How many compound liberate $NH_3$ on heating from the following?
$(NH_4)_2SO_4, (NH_4)_2CO_3, NH_4Cl,NH_4NO_3,(NH_4)_2Cr_2O_7$

1980340_1728464_ans_c5cb577fc3ad4be1a829205e73a43990.jpg

A compound $(A)$ on heating with an excess of caustic soda solution liberates a gas $(B)$ which gives white fumes on exposure to $HCl$ . Heating it continued to expel the gas completely. The resultant alkaline solution again liberates the same gas $(B)$ with zinc powder. However, the compound $(A)$ when heated alone, does not give nitrogen. Identify $(A)$ and $(B)$ .

1629045_1728799_ans_ac081a29b6c74510a8177987733034ed.jpg

Write short notes on:
(i) Available chlorine.

1961969_1728800_ans_e048c2449e464db799e563195a2dd0ed.jpeg

Describe the principle of manufacture with conditions of the following compounds:
Nitric acid by Ostwald's process.

1625310_1728641_ans_3b50440c57c8451fa32540f8d460a981.jpg

Describe the principle of manufacture with conditions of the following compounds:
White phosphorous from bone ash by electrothermic method.

Bone ash is heated with H₂SO₄ then orthophosphoric acid is obtained which on strong heating gives metaphosphoric acid.

Ca₃(PO₄)₂ + 3H₂SO₄ ——-> 2H₃PO₄ + 3CaSO₄

H₃PO₄ ——> HPO₃ (meta phosphoric acid) + H₂O

Meta phosphoric acid is mixed with coke and then distilled.

4HPO₃ + 10 C ——> 2H₂O + P₄ (white phosphorus)+ 10 CO

Vapors of phosphorus are condensed in water. White P is insoluble in H₂O therefore it settles down in the form of solid.

Electro-thermal process:
Mixture of calcium phosphate, silica and coke is heated in an electric furnace. Electric furnace contains carbon electrode. On passing current temperature rises upto 1500^o C and following reactions takes places:-

Ca₃(PO₄)₂ (bone ash) + 3SiO₂ ——–> 3 CaSiO₃ (slag) + P2O5

2 P₂O₅ + 10C —–> P₄ (white phosphorus) + 10CO

Calcium silicate is removed as slag. The vapors of phosphorus are condensed in water. White Phosphorus is insoluble in H₂O. Therefore it settles down in the form of solid.

Complete the following reactions:
$XeF_6 + SbF_5\rightarrow$

1676375_1728638_ans_6de7c735e10b40a6b2f40e4474170655.jpg

Match LIst-I with List-II:

1679838_1729089_ans_9eb89e594dcf4e9096def8ac817b7f44.jpg

The following flow diagram represents the industrial preparation of nitric acid from ammonia.
Which of the following options describes the reagents, products, and reaction conditions?

Option (p) (q) (r) (s)
(A) Catalyst and high pressure Cool $NO_2$ $H_2O$ and $O_2$
(B) Catalyst Cool $N_2O$ $HNO_3$ and $O_2$
(C) Catalyst and high pressure High pressure $NO_2$ $H_2O$ and $O_2$
(D) High pressure catalyst $N_2O_3$ $HNO_3$

[Enter the correct option e.g. if the answer is option C enter C]

$4NH_3(g) + 5O_2 \overset{platinum / Rhodium catalyst} {\underset{850^o C\,5 \, atmosphere} {\longrightarrow}} 4NO(g)$

$4NO_(g) + O_2$ (from air)

$\overset { cool \,to }{ \underset { -25^o C }{ \rightleftarrows } }$

$H_2O + NO_2 + O_2 \rightarrow HNO_3 + NO.$

p-catalyst and high pressure
q-cool
r-

$NO_2$
s-

$H_2O$ and

$O_2$

Option A is correct.

Account for the following:
Noble gases have comparatively large atomic sizes.

1659669_1777831_ans_a5449b03e0524b21aa87898566fdc976.jpg

Nitric acid forms an oxide of nitrogen on reaction with $P_{4}O_{10}$ .Write the resonating structures of the oxide of nitrogen formed.

The resonating structures are as shown in the figure.

1674465_1796751_ans_0e5d9b69b5dd49e497c7c7bf88354a65.png

Under what conditions can hydrogen be made to combine with nitrogen?
Name the product in the following case and write the equation for it.

Three volumes of hydrogen and one volume of nitrogen react at temperature

$450-500^oC$ and pressure

$200-900\ atm$ in the presence of finely divided iron catalyst with molybdenum as promoter to give ammonia.

$N_2+3H_2 \rightleftharpoons 2NH_3$

Of the two gases, ammonia and hydrogen chloride which is more dense ? Name the method of collection of this gas.

HCl gas is more dense [V.D. = 18.25, V.D. of ammonia = 8.5] and it is collected by the upward displacement of air.

X, Y and Z are three crystalline solids which are soluble in water and have a common anion. To help you to identify X, Y and Z you are provided with the following experimental observations. Copy and complete the corresponding inferences.
Write the equations for the following reactions:
(1) X and concentrated sulphuric acid (below $200^\circ$ )
(2) Action of heat on Y.
(3) Concentrated nitric acid is added to copper turnings kept in a beaker.

(i)

$KNO_3 + H_2SO_4 \overset{<200^\circ}{\longrightarrow} KHSO_4 + HNO_3$

(ii)

$2Pb(NO_3)_2 \xrightarrow{\triangle} 2PbO+4NO_2 + O_2$

(iii)

$Cu + 4HNO_3 \rightarrow Cu(NO_3)_2 + H_2O + 2NO_2$

Name a drying agent for ammonia. Why are other drying agents such as $P_2O_5$ and $CaCl_2$ are not used ?

The drying agent used is

$CaO$ in the case of ammonia.
Other drying agents like

$P_2O_5$ and

$CaCl_2$ are not used. As ammonia being basic reacts with them.

$6NH_3 + P_2O_5 + 3H_2O \rightarrow 2(NH_4)_3PO_4$

$CaCl_2 + 4NH_3 \rightarrow CaCl_2.4NH_3$

Give two examples to show the anamolus behaviour of fluorine.

1. Fluorine exhibits only

$(-1)$ oxidation state whereas other halogens exhibit

$+1, +3, +5$ and

$+7$ oxidation state also.

2. The anomalous behaviour of fluorine is due to its

(i) small size

(ii) highest electronegativity

(iii) low

$F-F$ bond dissociation enthalpy

(iv) non-availability of d-orbitals in its valence shell.

This is further explained as under:

1. Due to its small size, the three lone pair of electrons on each

$F$ atom in

$F - F$ molecule, repel the bond pair. As a result,

$F - F$ bond dissociation energy is lower than that of

$Cl - Cl$ bond.

2. Due to the non-availability of d-orbitals in its valence shell, fluorine can not expand its octet. Therefore, fluorine shows only an oxidation state of

$-1$ . All other halogens, due to the presence of d-orbitals, show a positive oxidation state of

$+1, +3, +5$ and

$+7$ besides the oxidation state of

$-1$ .

Name any five periods properties .

5 periodic properties are :

(i) Electron affinity

(ii) Atomic size
(iii) Metallic character
(iv) Non-metallic character
(v) Ionization energy

In the following reactions assign for underlined atom for product of complete hydrolysis at R.T.
A. If product is oxy acid with —ic suffix.
B. If product is oxy acid with —ous suffix.
C. If product are two oxy acids one with —ic suffix and another one with —ous suffix.
D. If product is not oxy acid, neither with —ic suffix nor with —ous suffix.
$H\underline NO_4+H_2O \longrightarrow HNO_3+H_2O_2$

Oxy acid :- An oxyacid, oxoacid, or ternary acid is an acid that contains oxygen. Specifically, it is a compound that contains hydrogen, oxygen, and at least one other element, with at least one hydrogen atom bonded to oxygen that can dissociate to produce the H⁺ cation and the anion of the acid.

In the given reaction :-

$HNO_{4} + H_{2}O \rightarrow HNO_{3} + H_{2}O_{2}$

$HNO_{3}$ : Nitric acid, also known as aqua fortis and spirit of niter, is a highly corrosive mineral acid. The pure compound is colorless, but older samples tend to acquire a yellow cast due to decomposition into oxides of nitrogen and water.

suffix is -ic.

Hence , As we see product is oxy acid with —ic suffix.

Hence , option A is correct .

Copy and complete the following table which refers to the industrial method for the preparation of ammonia and sulphuric acid :
Name of the compound Name of the process Catalytic equations
(with the catalyst)
Ammonia (i) ____ (ii) _
Sulphuric acid (iii) _ (iv) ___

(i) Haber’s process
(ii) See image
(iii) Contact process
(iv) See iamge
1890041_1909993_ans_814f14c5d7804e62a4d657df20e69430.png

Study the flow chart given and give balanced equations to represent the reactions A, B and C.

(A)

$Mg_3N_2 + 6H_2O \to 3Mg(OH)_2 + 2NH_3$

(B)

$NH_3+ HCl \to NH_4Cl$

(C)

$NH_4Cl + NaOH \xrightarrow{\Delta} NaCl + H_2O + NH_3\uparrow$

In the following reactions assign for underlined atom for product of complete hydrolysis at R.T.
A. If product is oxy acid with —ic suffix.
B. If product is oxy acid with —ous suffix.
C. If product are two oxy acids one with —ic suffix and another one with —ous suffix.
D. If product is not oxy acid, neither with —ic suffix nor with —ous suffix.
$\underline N_2O_4+H_2O \longrightarrow HNO_3+HNO_2$

1936724_1861991_ans_dcd4aafa06ff4fa393bab6039cf21450.jpg

In the following reactions assign for underlined atom for product of complete hydrolysis at R.T.
A. If product is oxy acid with —ic suffix.
B. If product is oxy acid with —ous suffix.
C. If product are two oxy acids one with —ic suffix and another one with —ous suffix.
D. If product is not oxy acid, neither with —ic suffix nor with —ous suffix.
$\underline N_2O_5+H_2O \longrightarrow HNO_3$

1937263_1861998_ans_e5586d2061f547e7835798efffc0d152.jpg

In the following reactions assign for underlined atom for product of complete hydrolysis at R.T.
A. If product is oxy acid with ic suffix.
B. If product is oxy acid with ous suffix.
C. If product are two oxy acids one with ic suffix and otherone with ous suffix.
D. If product is not oxy acid, neither with ic suffix nor with ous suffix.
$\underline N_2O_3+H_2O \longrightarrow HNO_2$

In the given reaction :-

$N_{2}O_{3} + H_{2}O \rightarrow HNO_{2}$

$HNO_{2}$ : Nitrous acid is a weak and monoprotic acid known only in solution, in the gas phase and in the form of nitrite salts. Nitrous acid is used to make diazonium salts from amines.

suffix is -ous.

Hence , If product is oxy acid with ous suffix.

Hence , option B is correct .

Name of the compound	Name of the process	Catalytic equations (with the catalyst)
Ammonia	(i) ________	(ii) _______
Sulphuric acid	(iii) _______	(iv) _______

$XeF_4$	$Xe{F_{5}}^{-}$	$F_2SeO_2$
$Xe{F_{3}}^{+}$	$XeOF_4$	$ClOF_3$
$IC{l_{4}}^{-}$	$SCl_2$	$OSF_4$

Name of the process	Temperature	Catalyst	Equation for the catalyzed reaction
Haber's process

$1$ litium	$2$	$13$	$14$ Carbon	$15$	$16$ Oxygen	$17$	$18$ neon
$X$			$S$		$P$	$L$
$Y$						$Q$
$Z$						$R$
						$T$

$3$	$4$	$5$	$6$	$7$	$8$	$9$	$10$
A	B	C	D	E	F	G	H
$11$	$12$	$13$	$14$	$15$	$16$	$17$	$18$
I	J	K	L	M	N	O	P

Option	(p)	(q)	(r)	(s)
(A)	Catalyst and high pressure	Cool	$NO_2$	$H_2O$ and $O_2$
(B)	Catalyst	Cool	$N_2O$	$HNO_3$ and $O_2$
(C)	Catalyst and high pressure	High pressure	$NO_2$	$H_2O$ and $O_2$
(D)	High pressure	catalyst	$N_2O_3$	$HNO_3$

The P-Block Elements - Class 12 Engineering Chemistry - Extra Questions

Fill in the blanks.In solid state, nitrogen occurs as __________.

Nitrolium is used as fertiliser. Explain.

(a) Draw the structures of the following: (i) XeF2Xe{F}_{2} (ii) BrF3Br{F}_{3}(b) Write the structural difference between white phosphorus and red phosphorus?

Name one halogen of period.

(a) Explain the Pauling scale for the determination of electronegativity. Give the disadvantages of Pauling scale.(b) How does Fluorine differ from other halogens?

Calculate the effective nuclear charge of the last electron in an atom whose configuration is 1s22s22p63s23p51s^2 2s^2 2p^6 3s^2 3p^5.

Write the names of Inert gases.

With reference to Haber's process, write the equation and the conditions required.

In the manufacture of nitric acid by Ostwald's process,___________ as a dehydrating agent is used to convert 68%68\% by mass of HNO3HNO_3 to 98%98\% by mass of HNO3HNO_3?

What are noble gases? Name all in the order of their increasing density.

LiILiI is soluble in water but LiFLiF is not, why?

In how many of the following species the central atom has two lone pairs of electrons ?XeF4XeF_4XeF5−Xe{F_{5}}^{-}F2SeO2F_2SeO_2XeF3+Xe{F_{3}}^{+}XeOF4XeOF_4ClOF3ClOF_3ICl4−IC{l_{4}}^{-}SCl2SCl_2OSF4OSF_4

It is likely that Ar will form the anion Ar−^-. If true enter 1, else enter 0.

Peroxonitrous acid is an unstable intermediate formed in the oxidation of HNO2HNO_2 by H2O2H_2O_2. "Peroxonitrous acid has the same formula as nitric acid, HNO3HNO_3."Answer whether the above statement is true or false.If true enter 1, else 0.

The tendency to form clathrates decreases down the group.

Maximum acidic character is shown by the oxyacids of halogens with oxidation number of halogens as ____________ .

Arrange the following in the increasing order of bond energy: F2<Cl2<O2<N2{ F }_{ 2 }<{ Cl }_{ 2 }<{ O }_{ 2 }<{ N }_{ 2 }If true enter 1, else enter 0.

In the following reaction XeF2+BrO3−+H2O⟶Xe+BrO4−+2HFXeF_2 + {BrO_3}^- + H_2O\longrightarrow Xe + {BrO_4}^- + 2HF equivalentmassofBrO3−=molarmass..........\displaystyle equivalent \:mass \:of \:{BrO_3}^-=\frac{molar \: mass}{..........}

Number of phases in the following equilibrium is : Ra(s)⟶Rn(g)+He(g)Ra(s)\longrightarrow Rn( g) + He(g)

For inert monatomic gases, CPCV=5x\displaystyle \frac{C_P}{C_V}=\frac{5}{x}. The value of x is _____ .

When Mg3N2Mg_3N_2 react with H2OH_2O, then how many type of gaseous product(s) is/are formed ?

In NO−3NO_3^- ion, find the number of bond pairs and lone pairs of electrons on nitrogen atoms. [If the answer is 2 and 4, represent as 24]

Find the sum of atomicity of nitrogen and phosphorous.

Rank the bond length of the bond below in the molecules on the left column with longest as 1 and shortest as 4Match the following.

How many number of faces are there in P4P_4 molecule?

The electronic configuration of an element is 1s2,2s2,2p6,3s23p31s^2, 2s^2, 2p^6, 3s^2 3p^3. What is the atomic number (X) of the element which is just below the above given element in the periodic table. Enter the value of XX.

The atomicity of phosphorus is X and the P-P-P bond angle is Y. What are X and Y?[If answers are 22 and 9090, represent as 290]

Observe the chemical reaction:P4+3NaOH+3H2O→P_4 + 3NaOH +3 H_2O \rightarrow 3NaH2PO2+PH33NaH_2PO_2+PH_3If the reaction is true enter 1 else 0

In Nessler's reagent for the detection of ammonia, the active species is ______.H2Cl2H_2Cl_2HgI2−4HgI_4^{2-}

Write balanced chemical equations for the reaction of a burning of aluminum in the air.

Why is helium used in weather observation balloons?

Helium is the most abundant Noble gas in the universeIf this is true enter 1, if false enter 0.

How is ammonia manufactured industrially?

Explain why fluorine forms only one oxoacid, HOF.

Give reasons for the following:R3P=OR_{3}P = O exists but R3N=OR_{3}N = O does not, RR is an alkyl group?

How are xenon fluorides XeF2, XeF4XeF_{2},\ XeF_{4} and XeF6XeF_{6} obtained?

(a)Account for the following:(i)Acidic character increase from HFHF to HIHI.(ii)There is a large difference between the melting and boiling points of oxygen and sulphur.(iii) Nitrogen does not form pentahalide.(b) Draw the structures of the following:(i) ClF3ClF_3(ii) XeF4XeF_{4}

Phosphorus has valencies of 3 and 5.What is the formula of the two oxides of phosphorus?

Draw the structures of the following molecules:(i) N2O5N_{2}O_{5} (ii) XeF2XeF_{2}

Account for the following:(i) Bi(V)Bi\left(V\right) is a stronger oxidizing agent than Sb(V)Sb\left(V\right).(ii) N−NN-N single bond is weaker than P−PP-P single bond.(iii) Noble gases have very low boiling points.

Draw the structures of the following molecules:(i) XeF6XeF_{6} (ii) H2S2O7H_{2}S_{2}O_{7}

(a) Draw the structures of the following molecules:(i) XeOF4XeO{F}_{4}(ii) H2SO4{H}_{2}S{O}_{4}(b) Write the structural difference between white phosphorus and red phosphorus.

(a) Draw structure of the following compounds:(i) XeF4Xe{F}_{4} (ii) N2O5{N}_{2}{O}_{5}(b) Write the structural difference between white phosphorus and red phosphorus.

Name a compound of chlorine that is used as:(A) An disinfectant (B) An anesthetic (C) A bleaching agent

Chlorine does not exist in free state. Give reason.

Ammonia gas is collected by ______.(an upward displacement of air, a downward displacement of water, a downward displacement of air)

Some word/ words are missing in the following statements. You are required to rewrite the statements in the correct form using the appropriate word/ words:Magnesium nitride reacts with water to liberate ammonia.

Study the figure given below and answer the questions that follow:Name another gas which has the same property and can be demonstrated through this experiment.

Copy and complete the following table relating to important industrial process:Name of the processTemperatureCatalystEquation for thecatalyzed reactionHaber's process

The following questions are based on the preparation of ammonia gas in the laboratory:Explain why ammonium nitrate is not used in the preparation of ammonia?

The following questions are based on the preparation of ammonia gas in the laboratory:Name the compound normally used as a drying agent during the process.

The following questions are based on the preparation of ammonia gas in the laboratory:How is ammonia gas collected?

The following questions are based on the preparation of ammonia gas in the laboratory:Explain why it is not collected over water?

Explain how does nitrogen exhibit anomalous behaviour amongst group 1515 elements.

Describe anomalous behaviour of fluorine with the other elements of group 1717 with reference to:Hydrogen bonding.

Why nitrogen exists as diatomic molecule (N2)(N_2) and Phosphorus as P4P_4?

Give balanced equations and principle involved in the manufacture of nitric acid (HNO3)(HNO_{3}) by Ostwald's process.

Describe anomalous behaviour of fluorine with the other elements of group 1717 with reference to:Polyhalide ions.

a) Write a chemical equation to prepare ammonia from ammonium chloride?b) Write a chemical equation to identify Cu+2Cu^{+2} & Ag+Ag^+ ions with the application of NH3NH_3?c) Draw a labeled diagram showing flowchart for the manufacture of ammonia?

Write the chemical formulae of four oxy acids of chlorine.

Describe anomalous behaviour of fluorine with the other elements of group 1717 with reference to:Oxidation state.

How are XeF2Xe{F}_{2} and XeF4Xe{F}_{4} prepared? Give their structures.

Write the balanced Chemical equation with condition involved in manufacture of nitric acid by ostwald's process.

Write the equations involved in the preparation of nitric acid by Ostwald's process by maintaining the reaction conditions.

Nitrogen does not form pentahalides. Give reason.

For the manufacture of Ammonia by Haber's process, write the equation and optimum conditions for maximum yield of ammonia.

Discuss Haber's process for industrial manufacture of ammonia.

Write the name of radioactive halogen?

Draw labelled diagram of Haber process for the manufacture of ammonia and write chemical equation?

The diagram showing the laboratory preparation of NH3{NH}_{3} is given.(a) What are the reactants used?(b) Why CaOCaO is used?(c) What is the reason behind not keeping the jar in the upward direction? (d) Write an experiment to identify presence of NH3{NH}_{3} in the gas jar.

Describe Haber process for the manufacture of ammonia?

Fluorine always shows-1 oxidation state. Why?

Some elements in pp-block shows allotropy.(a) What are the allotropic forms of sulphur?(b) (i) How will you manufacture Sulphuric Acid by contact process? (ii) What are inter halogen compounds?

(a) Account for the following: (i) H2O{H}_{2}O is a liquid while H2S{H}_{2}S is a gas. (ii) Noble gases have very low boiling points. (iii) NO2N{O}_{2} dimerises to N2O4{N}_{2}{O}_{4}.(b) (i) What are interhalogen compounds? (ii) Suggest any two examples on interhalogen compounds.

Why the elements of group 17 are coloured?

Explain the industrial preparation of ammonia by Haber's process. Also, write two physical properties of ammonia.

What are inter-halogen compounds?

Give a reason for the following.Inert gases do not form ions.

What are allotropes? Write the names of allotropes of phosphorus.

Fill in the blanks.
In solid state, nitrogen occurs as __________.

(a) Draw the structures of the following:
(i) $Xe{F}_{2}$ (ii) $Br{F}_{3}$
(b) Write the structural difference between white phosphorus and red phosphorus?

(a) Explain the Pauling scale for the determination of electronegativity. Give the disadvantages of Pauling scale.
(b) How does Fluorine differ from other halogens?

Calculate the effective nuclear charge of the last electron in an atom whose configuration is $1s^2 2s^2 2p^6 3s^2 3p^5$ .

In the manufacture of nitric acid by Ostwald's process,___________ as a dehydrating agent is used to convert $68\%$ by mass of $HNO_3$ to $98\%$ by mass of $HNO_3$ ?

$LiI$ is soluble in water but $LiF$ is not, why?

In how many of the following species the central atom has two lone pairs of electrons ?
$XeF_4$
$Xe{F_{5}}^{-}$

$F_2SeO_2$
$Xe{F_{3}}^{+}$
$XeOF_4$

$ClOF_3$
$IC{l_{4}}^{-}$

$SCl_2$

$OSF_4$

It is likely that Ar will form the anion Ar $^-$ . If true enter 1, else enter 0.

Peroxonitrous acid is an unstable intermediate formed in the oxidation of $HNO_2$ by $H_2O_2$ .
"Peroxonitrous acid has the same formula as nitric acid, $HNO_3$ ."
Answer whether the above statement is true or false.If true enter 1, else 0.

ncreasing order of bond energy: ${ F }_{ 2 }<{ Cl }_{ 2 }<{ O }_{ 2 }<{ N }_{ 2 }$
If true enter 1, else enter 0.

In the following reaction
$XeF_2 + {BrO_3}^- + H_2O\longrightarrow Xe + {BrO_4}^- + 2HF$

$\displaystyle equivalent \:mass \:of \:{BrO_3}^-=\frac{molar \: mass}{..........}$

Number of phases in the following equilibrium is
$Ra(s)\longrightarrow Rn( g) + He(g)$

For inert monatomic gases, $\displaystyle \frac{C_P}{C_V}=\frac{5}{x}$ . The value of x is _____ .

When $Mg_3N_2$ react with $H_2O$ , then how many type of gaseous product(s) is/are formed ?

In $NO_3^-$ ion, find the number of bond pairs and lone pairs of electrons on nitrogen atoms.

[If the answer is 2 and 4, represent as 24]

Rank the bond length of the bond below in the molecules on the left column with longest as 1 and shortest as 4
Match the following.

How many number of faces are there in $P_4$ molecule?

The electronic configuration of an element is $1s^2, 2s^2, 2p^6, 3s^2 3p^3$ . What is the atomic number (X) of the element which is just below the above given element in the periodic table. Enter the value of $X$ .

The atomicity of phosphorus is X and the P-P-P bond angle is Y. What are X and Y?
[If answers are $2$ and $90$ , represent as 290]

Observe the chemical reaction:

$P_4 + 3NaOH +3 H_2O \rightarrow$ $3NaH_2PO_2+PH_3$

If the reaction is true enter 1 else 0

In Nessler's reagent for the detection of ammonia, the active species is ______.
$H_2Cl_2$
$HgI_4^{2-}$

Helium is the most abundant Noble gas in the universe
If this is true enter 1, if false enter 0.

Give reasons for the following:
$R_{3}P = O$ exists but $R_{3}N = O$ does not, $R$ is an alkyl group?

How are xenon fluorides $XeF_{2},\ XeF_{4}$ and $XeF_{6}$ obtained?

(a)Account for the following:
(i)Acidic character increase from $HF$ to $HI$ .
(ii)There is a large difference between the melting and boiling points of oxygen and sulphur.
(iii) Nitrogen does not form pentahalide.
(b) Draw the structures of the following:
(i) $ClF_3$
(ii) $XeF_{4}$

Phosphorus has valencies of 3 and 5.
What is the formula of the two oxides of phosphorus?

Draw the structures of the following molecules:
(i) $N_{2}O_{5}$ (ii) $XeF_{2}$

Account for the following:
(i) $Bi\left(V\right)$ is a stronger oxidizing agent than $Sb\left(V\right)$ .
(ii) $N-N$ single bond is weaker than $P-P$ single bond.
(iii) Noble gases have very low boiling points.

Draw the structures of the following molecules:
(i) $XeF_{6}$ (ii) $H_{2}S_{2}O_{7}$

(a) Draw the structures of the following molecules:
(i) $XeO{F}_{4}$
(ii) ${H}_{2}S{O}_{4}$
(b) Write the structural difference between white phosphorus and red phosphorus.

(a) Draw structure of the following compounds:
(i) $Xe{F}_{4}$ (ii) ${N}_{2}{O}_{5}$
(b) Write the structural difference between white phosphorus and red phosphorus.

Name a compound of chlorine that is used as:
(A) An disinfectant (B) An anesthetic (C) A bleaching agent

Ammonia gas is collected by ______.
(an upward displacement of air, a downward displacement of water, a downward displacement of air)

Some word/ words are missing in the following statements. You are required to rewrite the statements in the correct form using the appropriate word/ words:
Magnesium nitride reacts with water to liberate ammonia.

Study the figure given below and answer the questions that follow:
Name another gas which has the same property and can be demonstrated through this experiment.

Copy and complete the following table relating to important industrial process:
Name of the process Temperature Catalyst Equation for the
catalyzed reaction
Haber's process

The following questions are based on the preparation of ammonia gas in the laboratory:
Explain why ammonium nitrate is not used in the preparation of ammonia?

The following questions are based on the preparation of ammonia gas in the laboratory:
Name the compound normally used as a drying agent during the process.

The following questions are based on the preparation of ammonia gas in the laboratory:
How is ammonia gas collected?

The following questions are based on the preparation of ammonia gas in the laboratory:
Explain why it is not collected over water?

Explain how does nitrogen exhibit anomalous behaviour amongst group $15$ elements.

Describe anomalous behaviour of fluorine with the other elements of group $17$ with reference to:
Hydrogen bonding.

Why nitrogen exists as diatomic molecule $(N_2)$ and Phosphorus as $P_4$ ?

Give balanced equations and principle involved in the manufacture of nitric acid $(HNO_{3})$ by Ostwald's process.

Describe anomalous behaviour of fluorine with the other elements of group $17$ with reference to:
Polyhalide ions.

a) Write a chemical equation to prepare ammonia from ammonium chloride?
b) Write a chemical equation to identify $Cu^{+2}$ & $Ag^+$ ions with the application of $NH_3$ ?
c) Draw a labeled diagram showing flowchart for the manufacture of ammonia?

Describe anomalous behaviour of fluorine with the other elements of group $17$ with reference to:
Oxidation state.

How are $Xe{F}_{2}$ and $Xe{F}_{4}$ prepared? Give their structures.

The diagram showing the laboratory preparation of ${NH}_{3}$ is given.
(a) What are the reactants used?
(b) Why $CaO$ is used?
(c) What is the reason behind not keeping the jar in the upward direction?
(d) Write an experiment to identify presence of ${NH}_{3}$ in the gas jar.

Some elements in $p$ -block shows allotropy.
(a) What are the allotropic forms of sulphur?
(b) (i) How will you manufacture Sulphuric Acid by contact process?
(ii) What are inter halogen compounds?

(a) Account for the following:
(i) ${H}_{2}O$ is a liquid while ${H}_{2}S$ is a gas.
(ii) Noble gases have very low boiling points.
(iii) $N{O}_{2}$ dimerises to ${N}_{2}{O}_{4}$ .
(b) (i) What are interhalogen compounds?
(ii) Suggest any two examples on interhalogen compounds.

Give a reason for the following.
Inert gases do not form ions.

Explain why:
Nitrogen does not form pentahalides.

Explain why:
Hydride of sulphur is a gas while hydride of oxygen is a liquid.

Why ${ PCl }_{ 5 }$ exists but ${ NCl }_{ 5 }$ does not ?

Write the structure of chlorous acid $[HOClO]$ .

Find number of $p\pi-d\pi$ bonds in
(a) Disulphate (b) triphosphate (c) trimetaphosphate (d) trimer of ${SO}_{3}$ (e) ${P}_{4}{O}_{10}$ (f) ${P}_{4}{O}_{6}$

Which allotropic form of phosphorus has discrete tetrahedral ${P_4}$ molecules.

Solid phosphorus melts and evaporates at high temperature Gaseous phosphorus effuses at a rate that is $0.567$ times that of Ne in the same apparatus under the same conditions . How many atoms are in a molecule of gaseous phosphorus.

Find number of $p\pi -d\pi$ bonds in:
a) Disulphate b) Triphosphate c) Trimetaphosphate
d) Trimer of ${ SO }_{ 3 }$ e) ${ P }_{ 4 }{ O }_{ 10 }$ f) ${ P }_{ 4 }{ O }_{ 6 }$

From the artg of the periodic table given, answer the following questions
$1$ litium $2$ $13$ $14$ Carbon $15$ $16$ Oxygen $17$ $18$ neon
$X$ $S$ $P$ $L$
$Y$ $Q$
$Z$ $R$
$T$
Name the family of $L,Q,R,T$ .

Give reasons:
Xenon does not form fluorides such as $Xe{ F }_{ 3 }$ and $Xe{ F }_{ 5 }$

In the manufacture of nitric acid by Ostwald's process, write
The chemical equation for the dissolution of $NO_2$ in water.

Number of lone pairs on $Xe$ in $XeF_6$ is:

Arrange following Ions in order of decreasing ionic radii ${ Li }^{ +2 },{ He }^{ + },{ Be }^{ +3 }$ ?

$Mg:$ s-block: : Nitrogen:_________

Calculate the no of moles present in $2.044 \times 10^{23}$ number of Helium gas ?

Which of the following is a non-metal that remains liquid at room temperature?
Br, Cl, He, P

Why the elements of group $18$ are also known as noble gases?

Name :

The most abundant element in the earth's crust.

How $XeF_2$ and $XeF_4$ are prepared? What are their structure?

What is the action of
conc nitnic acid on ethane

Given reasons for the following:
Dioxygen is a gas but sulphur a solid.

One method of producing $NH_{3}$ is by heating ammonium chloride, $NH_{4}Cl$ , with $CaO$ .
$2NH_{4} Cl + CaO \rightarrow 2NH_{3} + CaCl_{2} + H_{2}O$
Explain why the reaction of $NH_{4}Cl$ with $CaO$ produces ammonia.

What is the action of $NaOH$ on ammonium salts?

Answer the following:
Name two chalcogens

Answer the following:
Which allotropic form of sulphur is more stable at room temperature?

The following statement is true under certain conditions. Mention the condition in each case in a few words.
Hydrogen reacts with nitrogen to form ammonia.

Name the element of group 17, which has the following properties:

Radioactive

In the known interahalogen compounds $AB_n$ what is maximum value of n ?