MCQ Questions for Class 11 Medical Chemistry The S-Block Elements Quiz 5

What supports proper nerve functioning?

0%
Sodium
0%
Magnesium
0%
Calcium
0%
Iron

What is used in synthesis of chlorophyll In C4 plants?

0%
Sodium
0%
Iron
0%
Potassium
0%
Aluminium

$X$ and

$Y$ are the second ionisation potentials of alkali and alkaline earth metals of same period, then :

0%
$X > Y$
0%
$X < Y$
0%
$X = Y$
0%
$X << Y$

Explanation

The general electronic configuration of Alkali metal is

$ns^{1}$ so if we remove first electron(first ionization energy) it will become octet configuration,so to remove next electron it requires more energy(second ionization energy) ,whereas the general electronic configuration of alkali earth metals is

$ns^{2}$ so the electrons can be lost easily.,so the second ionization energy of alkali metal is more than the alkali earth metal,so the order of ionization energy is

$X > Y$ .
Hence option A is correct.

Which of the following hydride is covalent and polymeric?

0%
${CaH_2}$
0%
${BeH_2}$
0%
NaH
0%
${BaH_2}$

Explanation

Due to small size and high Ionization energy,

$Be$ always form covalent bonds, but

$BeH_2$ is an unstable molecule due to incomplete octet so it forms polymer (

$BeH_2$ )n
Each beryllium atom is bonded to two hydrogen atoms and each hydrogen atom to two beryllium atoms. Now, beryllium has only two valence electrons and hydrogen only one, it is apparent that there are not sufficient electrons to form so many electron-pair bonds.

The monomeric

$BeH_2$ , if formed with normal bonds, would have only four electrons in the valence shell of the beryllium atom and would be electron-deficient and unstable. It polymerizes to remedy the electron deficiency.

The bonds formed cannot be explained by the classical theories of bonding. They are banana-shaped molecular orbitals holding three atoms

$Be ---- H ---- Be$ together and are called

$3$ centred

$2-$ electron (

$3c 2e$ ) bonds. It is an example of a cluster compound.

Hence option B is correct.

_____ does not exist in solid state.

0%
$NaHCO_3$
0%
$NaHSO_3$
0%
$LiHCO_3$
0%
$CaCO_3$

Explanation

Lithium carbonate has low solubility in water. Its solubility increases under a mild pressure of carbon dioxide and this effect is due to the formation of metastable bicarbonate which is more soluble.

So, the correct option is

$C$

Which of the following does not illustrate the anomalous properties of

$Li$ ?

0%
The m.p. and b.p. of $Li$ are comparatively high
0%
$Li$ is much softer than the other I group metals
0%
$Li$ forms a nitride ${Li_3N}$ unlike group I metals
0%
The ion of $Li$ and its compounds are more heavily hydrated than those of the rest of the group

Explanation

Anomalous behavior of lithium is due to extremely small size of lithium. Its cation on account of small size and high nuclear charge, lithium exerts the greatest polarizing effect out of all alkali metals on negative ion. Consequently, lithium ion possesses remarkable tendency towards solvation and develops covalent character in its compounds.

$Li$ differs from other alkali metals in the following respects:

(1) It is comparatively harder than other alkali metals. $Li$ cannot be stored in kerosene as it floats to the surface, due to its very low density. $Li$ is generally kept wrapped in paraffin wax.

(2) It can be melted in the dry air without losing its brilliance.

(3) Unlike other alkali metals, lithium is least reactive among all. It can be noticed by the following properties,

(i) It is not affected by air.

(ii) It decomposes water very slowly to liberate $H_2$ .

(iii) It hardly reacts with bromine while other alkali metals react violently.

(4) Lithium is the only alkali metal which directly reacts with $N_2$ to form lithium nitride ( $Li_3N$ )

(5) Lithium when heated in $NH_3$ forms amide, $Li_2NH$ while other metals form amides, $MNH_2$ .

(6) When burnt in air, lithium form $Li_2O$ sodium form $Na_2O$ and $Na_2O_2$ other alkali metals form monoxide, peroxide and superoxide.

(7) $Li_2O$ is less basic and less soluble in water than other alkali metals.

(8) $LiOH$ is a weaker base than $NaOH$ or $KOH$ and decomposes on heating.

(9) The ion of $Li$ and its compounds are more heavily hydrated than those of the rest of the group

Hence, option $B$ is correct.

Metallic sodium is used as a drying agent for :

0%
chloroform
0%
cyclohexane
0%
diisopropyl ether
0%
diethylamine

The different products of Na and Li in dry air are :

0%
$NaOH, Na_2O, Li_2O$
0%
$Na_2O, Na_3N, Li_2O, Li_3N$
0%
$Na_2O, Li_2O, Li_3, NH_3$
0%
$Na_2O, Li_3N, Li_2O$

Explanation

Li reacts with

$N_2$ and

$O_2$ of air forming

$Li_3N$ and

$Li_2O$ but Na reacts with only

$O_2$ forming

$Na_2O$ . It does not react with

$N_2$ forming

$Na_3N$ (it requires high temperature).

Considering their electron affinities, do you think the alkali metals can form an anion like

$\mathrm{M^-}$ , where M represents an alkali metal?

0%
Yes, due to stable $ns^1$ configuration.
0%
No, due to stable $ns^1$ configuration.
0%
Yes, due to stable $ns^2$ configuration.
0%
No, due to unstable $ns^2$ configuration.

In certain matters, lithium differs from other alkali metals, the main reason for this is:

0%
Small size of lithium atom and $Li^+$ ion
0%
Extremely high electro positivity of $Li$
0%
Greater hardness of $Li$
0%
Hydration of $Li^+$ ion

The increasing order of solubility is :

0%
${CaCO_3}$ , ${KHCO_3}$ , ${NaHCO_3}$
0%
${NaHCO_3}$ , ${KHCO_3}$ , ${CaCO_3}$
0%
${KHCO_3}$ , ${NaHCO_3}$ , ${CaCO_3}$
0%
${CaCO_3}$ , ${NaHCO_3}$ , ${KHCO_3}$

Explanation

Hint: Solubility means the tendency of a species to dissolve in any solvent.

Explanation:

$NaHCO_3$ and $KHCO_3$ dissociates as-

$NaHCO_3\rightarrow Na^++HCO_3^-$

$KHCO_3\rightarrow K^++HCO_3^-$

Both of them give same annion but the size of sodium ion is less than that of potassium. So, $NaHCO_3$ have low lattice energy than $KHCO_3$ and its tendency to dissolve in water is also low.

$CaCO_3$ dissociates as-

$CaCO_3\rightarrow Ca^{+2}+CO_3^{2-}$ .

$Ca^{+2}$ have high charge density than $K^+,Na^+$ so, it have low lattice energy than sodium bicarbonate and potassium bicarbonate and also have the lowest solubility.

The increasing order of solubility is-

$CaCO_3<NaHCO_3<KHCO_3$ .

Fianl Answer: The increasing order of solubility is-

$CaCO_3,NaHCO_3,KHCO_3$ .

Correct option (D).

In the table calcium lies above barium. Which one is more reactive?

0%
Calcium
0%
Barium
0%
Both are equally reactive
0%
Nothing could be predicted

Out of the given elements, which elements forms superoxide?

0%
$A$ and $B$
0%
$E$ and $G$
0%
$B$ and $D$
0%
$A$ and $C$

Explanation

E and G form super oxide due to stable lattice formed by the packing of bigger cations with bigger anions. E and G are K and Rb respectively. They form superoxides

$\displaystyle KO_2$ and

$\displaystyle RbO_2$ respectively.

The lightest alkaline earth metal is :

0%
$Be$
0%
$Mg$
0%
$Ca$
0%
$Ba$

Explanation

$Be$ is the lightest alkaline metals.

What is requirement for sodium in milligrams per day?

0%
400
0%
500
0%
600
0%
700

Explanation

The daily requirement of sodium is

$600 \ mg$ .

The function of "sodium pump" is a biological process operating in each and every cell of all animals. Which of the following biologically important ions is also a constituent of this pump?

0%
$K^+$
0%
$Fe^{2+}$
0%
$Ca^{2+}$
0%
$Mg^{2+}$

Explanation

The function of "sodium pump" is a biological process operating in each and every cell of all animals.

$K^+$ ion, a biologically important ions is also a constituent of this pump.

$Na^+$ is a major cation present in blood plasma (outside cells).

$K^+$ is major cation present in cytoplasm (inside the cells).
Higher concentration of

$K^+$ and lower concentration of

$Na^+$ ion is present inside cell and tissue.
Lower concentration of

$K^+$ and higher concentration of

$Na^+$ ion is present in fluid, bathing cells and tissues (blood plasma).

Which of the following statement is not correct?

0%
$KOH$ is a stronger alkali than $NaOH$
0%
Milk of magnesia is an aqueous suspension of $Mg(OH)_2$
0%
$MgO$ is a refractory material used for lining electrical furnaces
0%
$MgCl_2.\, 6H_2O$ on heating yields $Mg(OH)_2$

Lithopone, a white pigment, is the mixture of:

0%
$BaSO_4$ and $ZnS$
0%
$BaS$ and $ZnSO_4$
0%
$CaSO_4$ and $ZnS$
0%
$CaS$ and $ZnSO_4$

Which forms the strongest base?

0%
E
0%
F
0%
G
0%
H

Extremely electropositive metals are present in______in______ groups.

0%
IIA and IIIA
0%
IA and IIA
0%
IIIA and IVA
0%
IVA and VIIA

Explanation

The elements of group

$IA$ and

$IIA$ easily lose electrons to attain inert gas configuration. Thus they have highly electropositive nature. Thus the correct answer is option B

The most lightest alkaline earth metal is:

0%
$Be$
0%
$Mg$
0%
$Ca$
0%
$Ba$

Explanation

Calcium

$(Z=20),$ is the lightest alkaline earth metal, with a density of

$1.55 g/cm^3$ , lighter than both beryllium and magnesium.

Which of the following trace elements is present in virtually all potable water?

0%
Lead
0%
Sodium
0%
Manganese
0%
Mercury

Which of the following metal does not react with water?

0%
Beryllium
0%
Copper
0%
Iron
0%
Potassium

Explanation

Beryllium

$(Be)$ is the only alkaline earth metal that does not react with water. This is due to its small size and high ionization energy in relation to the other elements in the group.

The magnetic quantum number of the valence electron of sodium is:

0%
$2$
0%
$3$
0%
$1$
0%
$0$

Explanation

Electronic configuration of

$Na$ ( it has 11 electrons) is

$1s^2 2s^2 2p^6 3s^1$ .

Here the valence electron is in

$3s$ orbitals (

$3s^1$ ). So, the orbital is s - orbital. The

$l$ value (Azimuthal quantum number) of this

$s\ -$ orbital is 0, so the magnetic quantum number will zero i.e.

$m$ value is 0.

Largest difference in radii is found in which of the following pair?

0%
$Li, Na$
0%
$Na,K$
0%
$K, Rb$
0%
$Rb, Cs$

Explanation

Radii of atoms increase as we go down the group due to the addition of extra energy shell. The nuclear charge also increases on moving down the group but the influence of addition of energy shell predominates. This predomination is larger in case when we move from

$Na$ to

$K$ among all the options given.

Hence, option

$B$ is correct.

Sodium on heating with moist air produces:

0%
$NaO$
0%
$NaOH$
0%
$Na_2O$
0%
$Na_2CO_3$

Explanation

Sodium when exposed to air, the surface rapidly tarnishes, darkening at first and then forming a white coating of sodium hydroxide and sodium carbonate. It reacts exothermically with water, to the point that sufficiently large pieces melt to a sphere and may explode; this reaction produces sodium hydroxide and flammable hydrogen gas.

$Na + H_2O \rightarrow NaOH + H_2O$

Which of the following alkaline earth metals do not give characteristic colour to the flame?

0%
$Be$
0%
$Mg$
0%
$Ca$
0%
Both A and B

Nitrolim is a mixture of :

0%
$CaC_2$ and graphite
0%
$CaCN_2$ and graphite
0%
$Ca(CN)_2$ and graphite
0%
$CaCN_2+N_2$

Explanation

$CaC_2 +N_2\longrightarrow CaCN_2 +C$

When nitrogen is passed over calcium carbide at a suitable high temperature, we get a mixture of

$CaCN_2 + Graphite (C)$ known as nitrolim which is a nitrogenous fertiliser."

Caustic alkalis are corrosive.

0%
True
0%
False

Potassium hydroxide is a good conductor of an electric current in the:

0%
gaseous state only
0%
molten (fused) state only
0%
solid state only
0%
solid and molten (fused) states
0%
molten (fused) state and in aqueous solution

Explanation

Option $(E)$ is correct.

Potassium hydroxide is a good conductor of an electric current in the molten (fused) state and in aqueous solution. When it is in solid state it cannot conduct electricity but it can conduct electricity in aqueous solution state or molten state. This is because it is an ionic compound. Ionic compounds are made of charged ions which are held tightly in solid state but become mobile in molten or aqueous solution state. The movement of these mobile ions between electrodes helps in conducting electricity.

____________ were discovered by bombarding beryllium with alpha particles.

0%
Neutrons
0%
Protons
0%
Electrons
0%
None of these

Explanation

Neutrons are discovered by bombarding berylium with alpha particals.

$_2Be^4 +_2He^4 \rightarrow _6C^{12} + _0n^1$

Among the following which can form ions with a

$2+$ charge?

0%
Alkali metal
0%
Alkaline earth metal
0%
Transition metal
0%
Halogen
0%
Noble gas

What is the correct formula for lithium fluoride?

0%
$LiF$
0%
${Li}_{2}{F}_{2}$
0%
${Li}_{3}{F}_{9}$
0%
$Li{F}_{7}$
0%
${Li}_{7}{F}_{19}$

Explanation

$LiF$ is the correct formula for lithium fluoride.

$Li$ has a +1 charge and

$F$ has a -1 charge so, when they come together, to form

$LiF$ having an ionic bond.

Thomas slag is:

0%
$CaSiO_3$
0%
$Ca_3(PO_4)_2$
0%
$MnSiO_3$
0%
$CaCO_3$
0%
none of the above

Explanation

Thomas slag is tetracalcium phosphate

$\displaystyle Ca_4(PO_4)_2O$ . It has

$\dfrac{Ca}{P }$ ratio of 2. It was used as a fertiliser due to the higher solubility of tetracalcium phosphate relative to apatite minerals.

What happens when too much of sodium is in your diet?

0%
Cancer
0%
Damage nerve function
0%
Risk factor for heart disease
0%
Digestion

A severe shortage of what in body fluids, may cause a potentially fatal condition known as hypokalemia?

0%
Sodium
0%
Potassium
0%
Iron
0%
Silicon

Which element has high concentration in plants, as compared to sodium?

0%
Potassium
0%
Calcium
0%
Silicon
0%
none

What is used for generation of nerve impulses in animals?

0%
Sodium
0%
Magnesium
0%
Calcium
0%
Iron

What is the correct formula for calcium chloride?

0%
${Ca}_{2}{Cl}_{2}$
0%
$CaCl$
0%
$Ca{Cl}_{2}$
0%
$Ca{Cl}_{3}$
0%
${Ca}_{2}Cl$

Explanation

Calcium chloride is

$CaCl_2$ formed by

$Ca^{2+}$ and

$Cl^{1-}$ by criscross method.

Which alkali metals reacts with nitrogen to form a nitride?

0%
Li
0%
Na
0%
K
0%
All of these

Explanation

Lithium is the only alkali metals react with nitrogen to form nitride,

$Li_3N$ .

$6Li + N_2 \rightarrow 2Li_3N$

What helps in digestion and nutrient transport in humans?

0%
Iron
0%
Sodium
0%
Potassium
0%
None of the above

What happens if we take excess intake of potassium?

0%
Hypokalemia
0%
Hypertension
0%
Hyperkalemia
0%
Low blood pressure

Which of the following forms only covalent bonds with other elements?

0%
Calcium
0%
Barium
0%
Radium
0%
Beryllium

Among the alkaline earth metals, the element forming predominantly covalent compound is:

0%
beryllium
0%
barium
0%
strontium
0%
calcium

Explanation

Option

$(B)$ is correct.

Beryllium predominantly forms covalent compound due to its small size (can't ionize easily). It has a smaller atomic radius and a large effective nuclear charge, it forms a covalent bond.

Beryllium shows a diagonal relationship with aluminium.

Which of the following physical property of beryllium makes it perfect aerospace material?

0%
High thermal conductivity
0%
Low density
0%
Both $A$ and $B$
0%
Beryllium is not suitable for aerospace mateerial

Which of the following hydroxide is amphoteric?

0%
Beryllium
0%
Calcium
0%
Radium
0%
Magnesium

Explanation

Explanation:

An amphoteric hydroxide is one that can react with acid as well as a base.
Metal hydroxides are usually basic whereas that of non-metals are acidic.
Beryllium shows the diagonal relationship with Aluminium. Therefore, like Aluminium its hydroxide is also amphoteric in nature.
The reactions of $Be{(OH)}_{2}$ with acid and base are as follows:

Hence, option $A$ is the correct answer.

Which of the following alkali metal did not easily tarnish in air?

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

Explanation

Option

$(A)$ is correct.

$Be$ does not easily tarnish in the air because the surface of beryllium metal is covered with a thin layer of oxide that helps protect the metal from attack by air. It does not oxidize in the air even at 600

$^°C$ .

Which of the following has highest melting point?

0%
Magnesium
0%
Barium
0%
Calcium
0%
Beryllium

Which of the following is the main reason for the anomalous properties of beryllium?

0%
Small size
0%
High electronegativity
0%
High ionization energy
0%
Low electronegativity

Which of the following hydrolyze in aqueous solution?

0%
Barium salt
0%
Beryllium salt
0%
Calcium salt
0%
Radium salt

Explanation

Beryllium salts hydrolyze in aqueous solution producing

${H_3O}^+$ ions.This is due the formation of stronger

$Be-O$ bond.
Other salts do not hydrolyze in aqueous solution.

CBSE Questions for Class 11 Medical Chemistry The S-Block Elements Quiz 5 - 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 5 - MCQExams.com

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Practice Class 11 Medical Chemistry Quiz Questions and Answers

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