MCQ Questions for Class 12 Engineering Chemistry The P-Block Elements Quiz 4

Argon was discovered by :

0%
Rayleigh
0%
Ramsay
0%
Both (A) and (B)
0%
Frankland and Lockeyer

$\mathrm{V}\mathrm{A}$ group elements are known as:

0%
halogens
0%
normal elements
0%
chalcogens
0%
pnicogens

Bond angle in

$\mathrm{P}_{4}$ molecule is

0%
$60^{0}$
0%
$90^{0}$
0%
$120^{0}$
0%
$109^{0}28'$

Ammonia is dried over :

0%
Quick lime
0%
Slaked lime
0%
Phosphorus pentoxide
0%
Con. $\mathrm{H}_{2}\mathrm{S}\mathrm{O}_{4}$

Explanation

Correct Option: $A$

Explanation:

· Ammonia is dried on being passed through quick lime.

· As ammonia is basic it can’t be dried with phosphorus pentoxide or concentrated sulfuric acid because both are acidic in nature and there will be acid base reaction will happen.

· Ammonia can’t be dried over $Ca{(OH)_2}$ . The reaction is as follows;

${\text{N}}{{\text{H}}_4}{\text{Cl}} + {\text{Ca}}{({\text{OH}})_2} \to {\text{CaC}}{{\text{l}}_2} + {\text{N}}{{\text{H}}_4}{\text{OH}}$

$2{\text{N}}{{\text{H}}_3} + {{\text{H}}_2}{\text{S}}{{\text{O}}_4} \to {\left( {{\text{N}}{{\text{H}}_4}} \right)_2}{\text{S}}{{\text{O}}_4}$

$4{\text{N}}{{\text{H}}_3} + {{\text{P}}_2}{{\text{O}}_5} + 3{{\text{H}}_2}{\text{O}} \to {\left( {{\text{N}}{{\text{H}}_4}} \right)_3}{\text{P}}{{\text{O}}_4}$

Ammonia can be dried with quick lime as quicklime is also basic as like ammonia so there will be no reaction takes place.

Calcium cyanamide on treatment with steam under pressure gives ammonia and :

0%
calcium carbonate
0%
calcium hydroxide
0%
calcium oxide
0%
calcium bicarbonate

Explanation

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

In Haber's process for the manufacture of ammonia, the catalyst used is :

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finely divided nickel
0%
finely divided molybdenum
0%
finely divided iron
0%
finely divided platinum

The catalytic promoter used in Haber's process is :

0%
Mo
0%
Ni
0%
Pt
0%
$\mathrm{V}_{2}\mathrm{O}_{5}$

Explanation

$Mo$ is used as catalytic promoter in Haber's process.

Ionic radius (in

$\mathrm{A}^{\mathrm{o}}$ ) of

$\mathrm{A}\mathrm{s}^{3+},\mathrm{S}\mathrm{b}^{3+}$ and

$\mathrm{B}\mathrm{i}^{3+}$ follow the order :

0%
$\mathrm{S}\mathrm{b}^{3+}>\mathrm{B}\mathrm{i}^{3+}$
0%
$\mathrm{S}\mathrm{b}^{3+}>\mathrm{B}\mathrm{i}^{3+}>\mathrm{A}\mathrm{s}^{3+}$
0%
$\mathrm{B}\mathrm{i}^{3+}>\mathrm{A}\mathrm{s}^{3+}>\mathrm{S}\mathrm{b}^{3+}$
0%
$\mathrm{B}\mathrm{i}^{3+}>\mathrm{S}\mathrm{b}^{3+}>\mathrm{A}\mathrm{s}^{3+}$

Electronegativity of inert gases is :

0%
low
0%
high
0%
zero
0%
abnormally high

Explanation

Electronegativity of inert gases is zero as they have no tendency to attract the shared

$e^{-}$ .

Since the noble gases already have eight electrons in their outer shells, they don't want to attract any more.

Since electronegativity measures the amount of attraction between an atom and an electron, noble gases do not have electronegativity.

Option C is correct.

Non metals are usually poor conductors of heat and electricity. They are non-lustrous, non-sonorous, non-malleable and are coloured.

Non-metal other than carbon, which shows allotropy is:

0%
sulphur
0%
phosphorus
0%
nitrogen
0%
both A and B

The molecular formula of phosphorous is:

0%
$P_{1}$
0%
$P_{4}$
0%
$P_{2}$
0%
$P_{5}$

Explanation

The molecular formula of phosphorous is

$P_{4}$ .
White phosphorus, in gaseous state and as waxy solid consists of

$P_4$ tetrahedra.

The colour and state of phosphorus pentoxide is :

0%
white crystalline solid
0%
white amorphous liquid
0%
blue crystalline
0%
blue colour liquid

Zero group elements are known as____________.

0%
alkali metals
0%
alkaline earth metals
0%
transition metals
0%
inert gases

Explanation

The elements of group

$0$ have stable complete octate configuration. As a result, they do not react with other elements easily, i.e., they have inert behavior. Hence they are also called inert gases.

Most abundant uncombined element present in atmosphere is :

0%
Ca
0%
Mg
0%
Al
0%
N

Explanation

Nitrogen gas

$N_2$ makes up about 78% of the atmosphere by volume.

Which is the most thermodynamically stable allotropic form of phosphorus?

0%
Red
0%
White
0%
Black
0%
Yellow

Among these ores the highest phosphorus content is in :

0%
chlorapatite
0%
phosphorite
0%
fluorspar
0%
all have equal content

Explanation

Phosphorite ore is the ore that has the highest phosphorus content.
Percentage of

$P$ in phosphorite

$=\frac {62}{279}\times 100=22.22$ %
In flourapatite and chlorapatite the percentage content of phosphorus is 20.32% and 19.62% respectively.

The percentage of p-character in the orbitals forming

P−PP−P is :

0%
25
0%
33
0%
50
0%
75

Explanation

$P_4$ , all P atoms are in

$sp^3$ hybridization so p-character in the orbitals forming PP bonds

$100*3/4 =75$ %.

Which one of these group off elements is also called the halogen family?

0%
Group 16
0%
Group 18
0%
Group 10
0%
Group 17

Essential constituents of plants and animal tissues are :

0%
N and P
0%
N and As
0%
Cu and Mg
0%
Ca and Mg

The most abundant element in the atmosphere is :

0%
Phosphorus
0%
Oxygen
0%
Nitrogen
0%
Carbon

Phosphorus normally exhibits a covalency of :

0%
$+3$ and $+5$
0%
$+2$ and $+3$
0%
$+1$ and $+2$
0%
$+3$ and $+4$

Explanation

Phosphorous acid

${ H }_{ 3 }{ PO }_{ 3 }$ , metaphosphorous acid

$HPO _{ 2 }$ has

$+3$ oxidation state.

Pyrophosphoric acid

${ H }_{ 4 }{ P }_{ 2 }{ O }_{ 7 }$ , orthophosphoric acid

$H _{ 3 }{ PO }_{ 4}$ has

$+5$ oxidation state.

Helium gas is used in observatory balloon.

0%
True
0%
False

Which of the following non-metals belongs to the halogen family?

0%
Flourine
0%
Chlorine
0%
Bromine
0%
All of the above

Helium is the lightest gas.

0%
True
0%
False

The word Argon means_____________.

0%
Noble
0%
Now
0%
Strange
0%
Lazy

Which of the following is a noble gas?

0%
$He$
0%
$N_2$
0%
$H_2$
0%
$O_2$

Explanation

$He$ is a noble gas with 2 electrons in outer shell.

An element X combines with hydrogen to form a compound

$NH_3$ . The element X is placed on the right side of the periodic table. What is true about the element X?
(a) Has

$3$ valence electrons
(b) Is a metal and is solid
(c) Is a non-metal and is a gas
(d) Has

$5$ valence electrons
(e)

$NH_3$ reacts with water to form a basic compound.

0%
(a), (b) and (c)
0%
(b), (c) and (d)
0%
(c), (d) and (e)
0%
(e), (a) and (b)

Explanation

X is N because it is placed on the right side of the periodic table & compound is

$NH_3$ . X is a non metal and valence electrons are

$5$ &

$NH_3+H_2O\rightarrow NH_4OH$ (Base)

Which element is monoatomic gas at room temperature?

0%
$Ne$
0%
$F$
0%
$O_2$
0%
$N_2$

Explanation

Ne is noble gas so it will exists as monoatomic gas at room temperature.
All other gases exists in dimer form as

$F_2, N_2\$ and

$\ O_2$ .

Neon gas is used in neon signs.

0%
True
0%
False

In the preparation of ammonia gas from ammonium chloride and calcium hydroxide, the reactants are ground thoroughly________

0%
to provide maximum surface area
0%
to provide maximum surface area
0%
to increase the number of particle
0%
None of these

What is the bond order of N-N bond in

$N_2O$ ?

0%
1
0%
1.5
0%
2
0%
2.5

Explanation

Bond order will be

$\frac{Total no. of bonds} {Total No. of canonical structures} = \frac{5}{2}=2.5$

The third structure is not possible as nitrogen cannot have two negative charges so we will consider only two structures.

In 1st structure there are three bonds between both nitrogen and in second structure there are two bonds so total bonds is 5.

Noble gases do not react because they have __________ electrons in their valence shell.

0%
3
0%
6
0%
1
0%
8

Ammonia can be collected by displacement of

0%
Water
0%
$Conc.{ H }_{ 2 }S{ O }_{ 4 }$
0%
Brine
0%
Mercury

The catalyst used in laboratory preparation of oxygen is:

0%
$MgO$
0%
$MnO_2$
0%
$Pt$
0%
$Fe$

Explanation

The catalyst used in the preparation of oxygen is

$MnO_2$ .

Which of the following has seven valence electrons?

0%
$Na^{+}$
0%
$Al$
0%
$F$
0%
$Ti$
0%
$B$

Explanation

We know that halogens have 7 electrons in their valence shell.

$F, Cl, Br, I$ are halogens.

Hence, option

$C$ is correct.

Which of the following pairs is obtained on heating ammonium dichromate?

0%
$\displaystyle { N }_{ 2 }$ and $\displaystyle { H }_{ 2 }O$
0%
$\displaystyle { N }_{ 2 }O$ and $\displaystyle { H }_{ 2 }O$
0%
$\displaystyle { NO }_{ 2 }$ and $\displaystyle { H }_{ 2 }O$
0%
$\displaystyle NO$ and $\displaystyle { NO }_{ 2 }$

Explanation

Ammonium dichromate on heating gives nitrogen, chromic oxide and water.

$\displaystyle { \left( { NH }_{ 4 } \right) }_{ 2 }{ Cr }_{ 2 }{ O }_{ 7 }\underrightarrow { \Delta } { N }_{ 2 }+{ Cr }_{ 2 }{ O }_{ 3 }+4{ H }_{ 2 }O$

Ammonia gas is not prepared by:

0%
Reduction of sodium nitrite or nitrate by the reaction of zinc dust and sodium hydroxide.
0%
Hydrolysis of calcium cyanamide.
0%
Heating ammonium chloride with slaked lime
0%
Heating of $(NH_4)_2Cr_2O_7$

What is found in silver deposits?

0%
Phosphorous
0%
Bismuth
0%
Copper
0%
Antimony

$N,P,As,Sb,Bi$ elements belong to:

0%
VA Group
0%
IV A Group
0%
VII A Group
0%
VIII A Group

Explanation

The VA group of the periodic group consists of nonmetals such as nitrogen, phosphorous, antimony, bismuth, arsenic.

The electronic configuration of elements given in question are:

N-

$1s^22s^22p^3$

P-

$1s^22s^22p^63s^22p^3$

As-

$3d^{10}4s^24p^3$

Sb-

$4d^{10}5s^25p^3$

Bi-

$4f^{14}5d^{10}6s^26p^3$

In all the configurations, the valence shell of the element has 5 electrons and as the group number is decided by number of valence shell electrons. That's why elements have group number VA.

White phosphorous

$({P}_{4})$ has:

0%
four $P-P$ single bonds
0%
four lone pair of electrons
0%
$P-P-P$ angle of ${ 60 }^{ o }$
0%
eight $P-P$ single bonds

Explanation

${P}_{4}$ molecule
Bond angle

$={ 60 }^{ o }$
Six P - P

$=$ single bond
Lone pair

$=$ 4 in each molecule

Urea is prepared by the chemical reaction of:

0%
acetamide and ethyl alcochol
0%
ammonium sulphate and calcium chloride
0%
ammonia and Carbon dioxide
0%
chlorine and water

Explanation

The chemical formula of urea is

$H_2N-CO-NH_2$

Urea is now prepared commercially in vast amounts from liquid ammonia and liquid carbon dioxide.

Fluorine, chlorine, bromine, and iodine form a family of related elements, known as:

0%
light gases
0%
halogens
0%
purines
0%
the aromatic ring

All noble gases are:

0%
colourlful
0%
colourless and odourless
0%
colourless and but have odour
0%
none of these

From the options given, which of the following is a noble gas?

0%
Gunpowder
0%
Iodine
0%
Boron
0%
Helium

Which of the following is the Metallic element in group-15?

0%
As
0%
Sb
0%
Bi
0%
P

Explanation

Down the group metallic properties increases

$Bi$ is the metallic element in group-15

Similarity of fluorine and oxygen may not be attributed to?

0%
Their atomic and ionic radii are closely similar.
0%
The atom of both elements attain an octet of electrons in their valence shell
0%
Both of them are highly electronegative elements.
0%
Both form stable $p \pi-p \pi$ multiple bonds with themselves.

In the third excited state, the number of unpaired electrons in chlorine atom is:

0%
5
0%
7
0%
3
0%
1

Explanation

The general electronic configuration of chlorine is

$[Ne] 3s^{2} 3p^{5}$ .

When electrons are excited in chlorine, the electrons enter into 3d subshell then the electronic configuration of chlorine is given as:

$[Ne] 3s^{1} 3p^{3} 3d^{3}$

Thus the number of unpaired electrons will be 7.

If a new noble gas is discovered then, what will be its atomic number?

0%
$87$
0%
$104$
0%
$118$
0%
$132$

Explanation

$Rn+32 = 86+ 32 = 118$

The atomic number of next inert gas to be discovered will be

$118$ .

The elements with atomic numbers

$2, 10, 18, 36, 54$ and

$86$ are collectively known as:

0%
alkaline earth metals
0%
inert gases
0%
halogens
0%
rare earths

Explanation

Zero group of Mendeleev's periodic table or the group

$18$ of long form of periodic table is comprised of six elements and these eleements are called as inert gases as trhese elements do not react (inert) with other elements due to their octet outer electronic configaration which is stable configaration. The electronic configuration is listed in the following table.

S.No	Element	Symbol	Atomic no.	Electronic configuration
1	Helium	He	2	1s $^2$
2	Neon	Ne	10	[He] 2s $^2$ 2p $^6$
3	Argon	Ar	18	[Ne] 3s $^2$ 3p $^6$
4	Krypton	Kr	36	[Ar] 3d $^{10}$ 4s $^2$ 4p $^6$
5	Xenon	Xe	54	[Kr] 4d $^{10}$ 5s $^2$ 5p $^6$
6	Radon	Rn	86	[Xe] 4f $^{14}$ 5d $^{10}$ 6s $^2$ 6p $^6$

Which of the following electronic configuration corresponds to an inert gas?

0%
$1s^{1}2s^{2}2p^{5}$
0%
$1s^{2}2s^{2}2p^{6}$
0%
$1s^{2}2s^{1}$
0%
$1s^{2}2s^{2}2p^{6}3s^{1}$

Explanation

Noble gases have full-filled configuration i.e the subshell are completely filled.

They have the general electronic configuration as

$ns^2 np^6$ .

Thus option B represents a noble gas.

CBSE Questions for Class 12 Engineering Chemistry The P-Block Elements Quiz 4 - MCQExams.com

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Practice Class 12 Engineering Chemistry Quiz Questions and Answers

CBSE Questions for Class 12 Engineering Chemistry The P-Block Elements Quiz 4 - MCQExams.com

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Practice Class 12 Engineering Chemistry Quiz Questions and Answers

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