MCQ Questions for Class 11 Medical Chemistry The S-Block Elements Quiz 8

${Be}_{2}C+4{H}_{2}O\longrightarrow 2X+{CH}_{4}$

$X+2OH\longrightarrow Y$
(X) and (Y) formed in the above two reactions are :

0%
${BeCO}_{3}$ and $Be\left(OH\right)_{2}$ respectively
0%
$Be\left(OH\right)_{2}$ and ${BeCl}_{2}$ respectively
0%
$Be\left(OH\right)_{2}$ and $\left[Be\left(OH\right)_{4}\right]^{2-}$ respectively
0%
$\left[Be\left(OH\right)_{4}\right]^{2-}$ and ${BeCl}_{2}$ respectively

Explanation

The reaction involved are-

$Be_2C+4H_2O \rightarrow 2Be(OH)_2 +CH_4$

Hence X is

$Be(OH)_2$

Now,

$Be(OH)_2 +2OH^{-} \rightarrow [Be(OH)_4]^{2-}$

So, Y is

$[Be(OH)_4]^{2-}$

The solubility of metal halides depends on their nature, lattice enthalpy and hydration enthalpy of the individual ions. Amongst fluorides of alkali metals, the lowest solubility of LiF in water is due to:

0%
ionic nature of lithium fluoride
0%
high lattice enthalpy
0%
high hydration enthalpy for lithium ion
0%
low ionisation enthalpy of lithium atom

Explanation

Lowest solubility of

$LiF$ is due to high lattice enthalpy which is higher than hydration enthalpy. Hence, the dissociation of

$Li-F$ bond becomes difficult.

When

$LiNO_{3}$ is heated, it gives oxide,

$Li_{2}O$ , whereas other alkali metal nitrates decompose to give corresponding :

0%
nitrite
0%
peroxide
0%
both nitrite and oxide
0%
none of these

Explanation

Due to the small size of

$Li^{+}$ , it is very polarizing and favours the formation of

$LiO_2$ .

$4LiO_3 \rightarrow 2Li_2O + 4NO_2 + O_2$

While other alkali metal nitrates decomposes to give corresponding nitrite.

$NaN{O}_{3} \xrightarrow{\Delta} NaN{O}_{2} + \cfrac{1}{2} {O}_{2}$

The main constituents of pearl are:

0%
ammonium sulphate and sodium carbonate
0%
aragonite are conchiolin
0%
calcium carbonate and magnesium carbonate
0%
calcium oxide and ammonium chloride

Explanation

The chief component of the nacre that constitutes the pearl is aragonite $(CaCO_3)$ . Nacre also contains a small amount of conchiolin, a hornlike organic substance (albuminoid) that is the main constituent of the mollusk's outer shell.

Which of the following is used as a sources of hydrogen for filling of balloons that is convenient and can be carried around?

0%
Lithium hydride
0%
Sodium borohydride
0%
Calcium metal
0%
Sodium formate

Which of the following elements does not form hydride by direct heating with dihydrogen?

0%
Be
0%
Mg
0%
Sr
0%
Ba

Explanation

All the elements except beryllium combine with hydrogen upon heating to form their hydrides,

$MH_2$

$BeH_2$ , however, can be prepared by the reaction of

$BeCl_2$ with

$LiAlH_4$ .

$2BeCl_2 + LiAlH_4 \rightarrow 2BeH_2 + LiCl + AlCl_3$

Which of the following reacts with water at a high rate?

0%
Li
0%
K
0%
Na
0%
Rb

Explanation

As we move down in a group, reactivity of elements with water increases.

Among the given first group members, Rb is the metal of

$5^{th}$ period, whereas all others are elements of period lower than 5.

Hence, Option "D" is the correct answer.

Which of the following statement(s) is/are CORRECT for

$Be^{+3}$ ?

0%
It is isoelectronic with $Li^{+2}$
0%
The value of degeneracy for $2^{nd}$ excited state is $3$
0%
On accepting two electrons, the value of neutron excess with change
0%
Number of degenerate orbitals in its $1^{st}$ excited state is $4$

Explanation

$Be^{+3}$ is isoelectronicwith $Li^{+2}$ . Both the ions are having 1 electron only in their valence shells. So they are isoelectronic with each other.

So the option A is the correct statement for $Be^{+3}$ .

Hence option A is correct.

Select the correct statement out of the following.

0%
calcium fluoride is soluble in water.
0%
barium sulfate is soluble in water.
0%
barium dioxide is soluble in water.
0%
magnesium sulfate is soluble in water.

Explanation

The solubility of a compound depends on the co-relation between lattice enthalpy and hydration enthalpy. If the hydration enthalpy is equal to or greater than the lattice enthalpy, then the salt is water-soluble. More the hydration enthalpy as compared to lattice enthalpy more will be the solubility of salt in water.
$MgSO_4$ is soluble in water but $BaSO_4$ is not because of the size of $Ba^{2+}$ and $SO_4^{2-}$ ions is very large which leads to higher lattice enthalpy than that of hydration enthalpy. Barium hydroxide and barium oxide, are partially soluble in water and Calcium Fluoride is also insoluble due to extremely high lattice energy.

Thus, option D is correct.

The products obtained on heating

$LiNO_3$ will be

0%
$LiNO_2+O_2$
0%
$Li_2O+NO_2+O_2$
0%
$Li_3N+O_2$
0%
$Li_2O+NO+O_2$

Explanation

$4LiNO_3 \longrightarrow 2Li_2O +4NO_2+ O_2$

Lithium nitrate behaves differently from other alkali metal nitrates. Lithium nitrate on thermal decomposition produces metal oxide,

$NO_2$ and

$O_2$ . While other alkali metal nitrate on heating produces metal nitrite and oxygen.

Which of the following metals can form nitride with nitrogen ?

0%
$Li$
0%
$Na$
0%
$Mn$
0%
$Ca$

Explanation

Lithium is the only alkali metal which combines directly with nitrigen to form lithium nitride.

$Li_{(s)}+N_{2(g)}\longrightarrow 2Li_3N_{(s)}$

As lithium is the smallest alkali metal,

$Li^+$ will have the highest positive charge density.

As nitride

$(N^{3-})$ ion is an extremely small highly charged anion, it forms stable ionic compound with cations of high positive charge density, i.e.

$Li^{+}$ .

Property of the alkaline earth metals that increases with their atomic number is:

0%
IE
0%
Solubility of their hydroxides
0%
Solubility of their sulphates
0%
Eletronegativity

Explanation

In alkaline earth metals as the atomic number increases the number of atomic orbitals increases. In case of hydroxides, the lattice energies are different because of medium of size of hydroxide ions decreases on moving from

$Be$ to

$Ba$ .This tend to increase the solubility and to overcome the counter-effect produced by decrease in hydration energy. Hence the solubility of alkaline earth metal hydroxides increases with increase in atomic number.

Whereas electronegativity, Solubility of their sulphates and IE decreases with increase in atomic number.

Hence option B is correct answer.

Dark blue solution of alkali earth metal in liq.ammonia produce ____on evaporation of ammonia?

0%
metal
0%
metal amide
0%
$[M(NH_3)_6]^+$
0%
hexaammoniated metal

Explanation

Dark blue solution of alkali earth metal in liquid ammonia produce

$[M(NH_3)_6]^{+}$ on evaporation of ammonia.

Hence option C is correct answer.

Which is the following is not true?

0%
Group $2$ elements are electropositive strong reducing agents but not as strong as a group $1$ elements
0%
the reducing power of group $2$ elements increases down the group
0%
$Be$ has the most negative standard reduction potential
0%
The magnesium cation is more easily reduced then the heavier members of the group

Select the incorrect statement:

0%
sodium and potassium are $6$ th and $7$ th most abundant element in the earth's crust
0%
$NaOH$ is hygroscopic in nature
0%
if a crystal of $NaOH$ is exposed to air for longer periods it potassium a white powder of $Na_{2}CO_{3}$
0%
lithium is an alkali metal and can be used in photoelectric cells

Which elements does not combine directly with nitrogen at high temperature?

0%
Li
0%
Rb
0%
Sr
0%
Mg

Explanation

Only

$Rb$ does not combine with

$N_2$ at high temperature. Because heavier metals like

$Rb$ are seen to be chemically inactive towards

$N_2$ upon heating.

Since the nitride ion holds a high formal charge

$(N^{3-})$ and contains an adverse molar ration of cations to anions

$(3:1)$

it is impossible to form a stable structure. But alkali metal

$Li$ can react with

$N_2$ at room temperature.

$Sr$ and

$Mg$ can react with

$N_2$ at high temperature.

So, the correct option is

$Rb$

Which of the following fluorides has lowest melting point?

0%
$BaF_2$
0%
$SrF_2$
0%
$CaF_2$
0%
$BeF_2$

Explanation

Solution:- (D)

$Be{F}_{2}$

Being covalent,

$Be{F}_{2}$ has the lowest melting point

$\left( 800 ℃ \right)$ while other fluorides melt at around

$1300 ℃$ .

The lattice energy of the carbonates of Mg, Ca, Sr and Ba follow the order :

0%
$Mg{CO}_3$ > $Ca{CO}_3$ > $Sr{CO}_3$ > $Ba{CO}_3$
0%
$Ca{CO}_3$ > $Sr{CO}_3$ > $Ba{CO}_3$ > $Mg{CO}_3$
0%
$Ba{CO}_3$ > $Sr{CO}_3$ > $Ca{CO}_3$ > $Mg{CO}_3$
0%
$Sr{CO}_3$ > $Mg{CO}_3$ > $Ca{CO}_3$ > $Ba{CO}_3$

Explanation

Order of lattice energy of carbonates is

$MgCO_3>CaCO_3>SrCO_3>BaCO_3$

This is because as the ionic radius increases, the lattice energy decreases.

Which among these does not represent the correct order?

0%
$MgO> Mg{Cl}_{2}> NaCl$ (Lattice energy)
0%
$Ca{F}_{2}> Sr{F}_{2}> B{F}_{2}$ (Solubility in water)
0%
$LiF> NaF> KF$ (solubility in water)
0%
Both b and c

Which of the following shows least melting point?

0%
$Be$
0%
$Mg$
0%
$Ca$
0%
$Sr$

Explanation

Ans :

$B$

$\rightarrow$

$Mg$

Generally melting point of the metals decreases down the group. But

$Mg$ has anomalously low melting point in group

$2$ .

Group

$2$ metals have metallic bonding. If we look at the crystal structure,

$Be$ &

$Mg$ are hexagonal close packed,

$Ca$ &

$Sr$ are face centered cubic.

At melting point,

$Be$ ,

$Ca$ and

$Sr$ are body centered where as

$Mg$ is hexagonal closed packed. Due to this arrangement,

$Mg$ shows least melting point

Which of the following compound is not soluble in water?

0%
LiF
0%
NaCl
0%
NaBr
0%
LiBr

Which of the following alkaline earth metal shows properties similar to

$Al$

0%
$Be$
0%
$Ca$
0%
$Sr$
0%
$Ba$

Explanation

Beryllium (Be) shows properties similar to

$Al$ .

This is because they show diagonal relationship. This diagonal relaitonship is due to the approxiamtely equal atomic and ionic radii of

$Be$ and

$Al$ .

Among the following metals, the most dense is:

0%
osmium
0%
chromium
0%
platinum
0%
gold

The correct order of increasing thermal stability of

$K_2CO_3,MgCO_3 \, CaCO_3$ and

$BeCO_3$ is:

0%
$BeCO_3 < MgCO_3 < CaCO_3 < K_2CO_3$
0%
$MgCO_3 < BeCO_3 < CaCO_3 < K_2CO_3$
0%
$K_2CO_3 < MgCO_3 < CaCO_3 < BeCO_3$
0%
$BeCO_3 < MgCO_3 < K_2CO_3 < .CaCO_3$

Explanation

In all cases, for a particular set of e.g. Group 1 or Group 2 compounds, the thermal stability increases down the group as the ionic radius of the cation increases, and its polarising power decreases.
Group 1 compounds tend to be more thermally stable than group 2 compounds because the cation has a smaller charge and a larger ionic radius, and so a lower polarising power. particularly when adjacent metals on the same period are compared.

Hence, the order of increasing thermal stability is

$BeCO_3<MgCO_3<CaCO_3<K_2CO_3$

Which of the following cannot react with

$NaOH$ ?

0%
$Be$
0%
$Fe$
0%
$Al$
0%
$Zn$

Oxidation state of oxygen in

${ KO }_{ 2 }$ is :

0%
$0$
0%
$-1$
0%
$-\frac { 1 }{ 2 }$
0%
$-2$

Explanation

It has only one electron in its valence shell and can only take the +1 oxidation state.

Now, in $KO_2$ , let oxidation number of oxygen be x.

Therefore, $1+2x=0$ as $K=+1$ and $KO_2$ is a neutral molecule.

The oxidation number of oxygen in $KO_2$ is $\cfrac{-1}{2}$

Beryllium and aluminium show many same characters but in which way these differ to each other:

0%
Show maximum covalency in their compounds
0%
Nature of oxides are amphoteric
0%
Form covalent halide
0%
Form polymeric hydride

Which of the following compounds on thermal decomposition yields a basic as well as an acidic oxide?

0%
$KClO_3$
0%
$NaNO_3$
0%
$K_2CO_3$
0%
$MgCO_3$

Explanation

$MgCO_3\xrightarrow{\Delta} MgO+CO_2$

Since oxides of metals are basic in nature,

$MgO$ is basic, and

$CO_2$ is acidic. Hence decoposition of

$MgCO_3$ yields both acidic and basic oxides

Which one of the following chlorides has maximum tendency to form hydrate?

0%
$BaCl_2$
0%
$NaCl$
0%
$MgCl_2$
0%
$LiCl$

Explanation

A correct option would be Lithium.
Lithium is the smallest in size amongst all. Hence

$Li^+$ ion polarises water molecule easily than the others. Water molecules get attached to

$Li^+$ as the water of crystallization. The common example is (

$LiCl.2H_2O$ ). As the size increases the polarising power of cation decreases, therefore, higher member of the group generally form anhydrous salt.

Which of the following in creasing order is NOT correct as per the property indicate against it?

0%
$CsCl < RbCl < KCl < NaCl < LiCl$ (Lattice energy)
0%
$LiOH < NaOH < KOH$ (Solubility in water)
0%
${Li^ + } < N{a^ + } < {K^ + } < R{b^ + } < C{s^ + }$ (Size of hydrated ion)
0%
$NaI < NaBr < NaCl < NaF$ (Lattice energy)

Which of the following on heating gives oxides quickly ?

0%
${ Na }_{ 2 }{ CO }_{ 3 }$
0%
${ K }_{ 2 }{ CO }_{ 3 }$
0%
${ Li }_{ 2 }{ CO }_{ 3 }$
0%
${ Rb }_{ 2 }{ CO }_{ 3 }$

Explanation

$N{a_2}C{O_3} \to state\,\,than\,\,L{i_2}C{O_3}$

${K_2}C{O_3}$ and

$R{b_2}C{O_3}$

Stablitiy of carbaonate

$\uparrow$ down the gap or size

$\uparrow CO_3^{2 - }$ more stable.

$L{i_2}C{o_3} \to L{i_2}O + C{o_2}$ .

Hence, option

$C$ is correct answer.

Beryllium hydroxide on reaction with acid forms

0%
hydrated $Be(NO_3)_2$
0%
anhydrous $Be(NO_3)_2$
0%
$\left[ { Be }_{ 4 }O({ NO }_{ 3 }{ ) }_{ 6 } \right]$
0%
None of these

In aqueous solution beryllium sulphate exist as:

0%
$[Be(H_2O)_4]SO_4$
0%
$[Be(H_2O)_6]SO_4$
0%
$[Be(H_2O)_3]SO_4$
0%
$[Be(H_2O)_5]SO_4$

Diagonal relationship is shown by:

0%
$Li$
0%
$Be$
0%
$B$
0%
all of these

Explanation

Hint: The diagonal relationship is shown by adjacent elements in the second and third periods.

Correct Answer:

$Option \ D$

Explanation of correct option:

The diagonal relationship is a resemblance of elements present diagonally in the second and third periods of the modern periodic table.
They have similar properties and the same electronegativity.
From the above picture, it is clear that $Li-Mg$ , $Be-Al$ , and $B-Si$ shoes similarities in their properties due to the diagonal relationship.

Thus, all of these are the correct answers.

$LiAlH_4$ is obtained by reacting an excess of _____ with an ethereal solution of

$AlCl_3$ :

0%
$LiCl$
0%
$LiH$
0%
$Li$
0%
$LiOH$

Explanation

$LiAlH_4$ is obtained by reacting an excess of ${LiH}$ with an ethereal solution of $AlCl_3$ .

$LiAlH_4$ is prepared from the reaction between lithium hydride $(LiH)$ and aluminium chloride.

$4LiH + AlCl_3 \rightarrow LiAlH_4 + 3 LiCl$

So the correct option is B

Zn and Cd metals do not show variable valency because:

0%
They have only two electrons in the outermost subshells
0%
Their d-subshells are completely filled
0%
Their d-subshells are partially filled
0%
They are relatively soft metals

Which of the following properties is not true for an alkali metal?

0%
Low atomic volume
0%
Low ionization energy
0%
Low density
0%
Low electronegativity

Which of the following illustrate the anomalous properties of Lithium?

0%
Lithium is softer than the other group I metals
0%
Lithium forms nitride, $Li_3N$ unlike other group I metals
0%
The melting and boiling point of Lithium are comparatively high
0%
none of these

Explanation

Similarities of lithium with magnesium and dissimilarities with that of the other members of the group

Lithium is a very strong element and is equally strong as magnesium.

Li forms $Li_3N$ with nitrogen.

It has high melting and boiling points. The boiling point of lithium is $1330$ degree centigrade that is comparable to that of magnesium which is $1100$ degrees.

Due to small size, the lithium atom has high ionization energy. Hence, it remains inactive to dry air, slowly reactivity with water, liquid bromine and forms a highly stable hydride unlike other alkali metals.

Excess of

$Na^+$ ions in human system causes

0%
High blood pressure
0%
anaemia
0%
Low blood pressure
0%
None of these

Explanation

Excess of

$Na^+$ ion causes hight B.P

Lithium selenide can be described as a cubic closest-packed array of selenide ions with lithium ions in all of the tetrahedral holes. Formula of lithium selenide is

0%
$L{i_2}Se$
0%
$LiSe$
0%
$LiS{e_2}$
0%
$L{i_3}Se$

Explanation

Answer(A):-

$Li_2Se$

If number of Se =Z , Number of Li = 2Z

Alkali earth metal nitrate that doesn't crystalize with

$H_{2}O$ molecules

0%
$Ba(NO_{3})_{2}$
0%
$Sr(NO_{3})_{2}$
0%
$Ca(NO_{3})_{2}$
0%
$Mg(NO_{3})_{2}$

Explanation

Solution:- (A)

$Ba{\left( N{O}_{3} \right)}_{2}$

$Ba{\left( N{O}_{3} \right)}_{2}$ does not crystallise with water molecules as moving down the group, the possibility of formation of hydrate decreases with the decrease in charge density.

Which one of the following species dose not exist under normal conditions?

0%
$Li_2$
0%
${ Be }_{ 2 }^{ + }$
0%
$Be_2$
0%
$B_2$

Which of the following property of Li and Be is different from the rest of the elements of their group ?

0%
smaller size
0%
Valence shell contains only one s and three- p-orbitals
0%
Higher covalent character exhibit in their compounds
0%
All of the above

Dry slaked line on treating with chlorine gives?

0%
slaked lime
0%
Bleaching powder
0%
Chlorinated calcium
0%
None

Explanation

${Ca}{(OH)}_{2} + {Cl}_{2} \rightarrow CaO{Cl}_{2} + Ca{Cl}_{2} + HCl$

When Dry slaked lime on treating with chlorine , Bleaching powder is formed

Which would be the best antifreeze to sprinkle on icy roads?

0%
$Urea$
0%
$NaCI$
0%
$CaC{l_2}$
0%
$A{l_2}{(S{O_4})_3}$

Which one of the following is true?

0%
Lithium on direct combination with nitrogen from $Li_3N$ .
0%
Magnesium on direct combination with nitrogen from $Mg_3N$ .
0%
Both a and b
0%
Lithium and magnesium form bicarbonates.

Which two processes are involved in the preparation of magnesium sulfate from dilute sulfuric
acid and an excess of magnesium oxide?

0%
Neutralisation and filtration
0%
Neutralisation and oxidation
0%
Thermal decomposition and filtration
0%
Thermal decomposition and oxidation

The magnitude of property X of five elements from the third period of the Periodic Table,

$P,Q,R,S$ and

$T$ is shown

$P,Q,R,S$ and

$T$ have cosecutive atomic numbers. The letters do not represent the symbols of the elements.
Which row correctly identifies property X and element R?

0%
property X - electrical conductivity ; element R - $Al$
0%
property X - electronegativity ; element $R - Si$
0%
property X - melting point ; element $R - Al$
0%
property X - meltingpoint ; element $R - Si$

Explanation

Graph

from this we can say that element R is

$Al$

1369879_1648958_ans_93a2776157bb4535a89818af4153d658.jpg

When dealing with a spillage of metallic sodium it is important that no toxic or flammable products are formed.
Which material should be used if there is a spillage of metallic sodium?

0%
Dilute hydrochloric acid
0%
Ethanol
0%
Sand
0%
Water spray

Metallic elements are described by their standard electrode potential,fusion enthalpy,atomic size, etc. The alkali metals are characterized by which of the following properties?

0%
High boiling point
0%
High negative standard electrode potential
0%
High density
0%
Large atomic size

CBSE Questions for Class 11 Medical Chemistry The S-Block Elements Quiz 8 - MCQExams.com

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Practice Class 11 Medical Chemistry Quiz Questions and Answers

CBSE Questions for Class 11 Medical Chemistry The S-Block Elements Quiz 8 - MCQExams.com

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Practice Class 11 Medical Chemistry Quiz Questions and Answers

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