JEE Main > Some pBlock Elements

Explore popular questions from Some pBlock Elements for JEE Main. This collection covers Some pBlock Elements previous year JEE Main questions hand picked by popular teachers.


Q 1.    

Correct4

Incorrect-1

In {tex} \mathrm { XeF } _ { 2 } , \mathrm { XeF } _ { 4 } , \mathrm { XeF } _ { 6 } {/tex} the number of lone pairs on {tex} \mathrm { Xe } {/tex} are respectively

A

{tex} 2,\ 3, \ 1 {/tex}

B

{tex} 1,\ 2, \ 3 {/tex}

C

{tex} 4, \ 1, \ 2 {/tex}

{tex} 3, \ 2, \ 1 {/tex}.

Explanation

Q 2.    

Correct4

Incorrect-1

Which of the following statements is true?

A

{tex}\mathrm{HF}{/tex} is less polar than {tex}\mathrm{HBr}{/tex}

B

Absolutely pure water does not contain any ions

Chemical bond formation takes place when forces of attraction overcome the forces of repulsion

D

In covalency transference of electron takes place.

Explanation


Q 3.    

Correct4

Incorrect-1

When {tex} \mathrm { H } _ { 2 } \mathrm { S } {/tex} is passed through {tex} \mathrm { Hg } _ { 2 } \mathrm { S } {/tex} we get

A

{tex} \mathrm { HgS } {/tex}

B

{tex} \mathrm { HgS } + \mathrm { Hg } _ { 2 } \mathrm { S } {/tex}

{tex} \mathrm { Hg } _ { 2 } \mathrm { S } + \mathrm { Hg } {/tex}

D

{tex} \mathrm { Hg } _ { 2 } \mathrm { S } {/tex}.

Explanation

Q 4.    

Correct4

Incorrect-1

Glass is a

A

micro-crystalline solid

super-cooled liquid

C

gel

D

polymeric mixture.

Explanation


Q 5.    

Correct4

Incorrect-1

Graphite is a soft solid lubricant extremely difficult is to melt. The reason for this anomalous behaviour is that graphite

A

is a non-crystalline substance

B

is an allotropic form of diamond

C

has molecules of variable molecular masses like polymers

has carbon atoms arranged in large plates of rings of strongly bound carbon atoms with weak interplate bonds.

Explanation


Q 6.    

Correct4

Incorrect-1

Which one of the following processes will produce hard water?

A

Saturation of water with {tex} \mathrm { CaCO } _ { 3 } {/tex}

B

Saturation of water with {tex} \mathrm { MgCO } _ { 3 } {/tex}

Saturation of water with {tex} \mathrm { CaSO } _ { 4 } {/tex}

D

Addition of {tex} \mathrm { Na } _ { 2 } \mathrm { SO } _ { 4 } {/tex} to water.

Explanation


Q 7.    

Correct4

Incorrect-1

Which one of the following pairs of molecules will have permanent dipole moments for both members?

A

{tex} \mathrm { SiF } _ { 4 } {/tex} and {tex} \mathrm { NO } _ { 2 } {/tex}

B

{tex} \mathrm { NO } _ { 2 } {/tex} and {tex} \mathrm { CO } _ { 2 } {/tex}

{tex} \mathrm { NO } _ { 2 } {/tex} and {tex} \mathrm { O } _ { 3 } {/tex}

D

{tex} \mathrm { SiF } _ { 4 } {/tex} and {tex} \mathrm { CO } _ { 2 } {/tex}.

Explanation


Q 8.    

Correct4

Incorrect-1

Which one of the following substances has the highest proton affinity?

A

{tex} \mathrm { H } _ { 2 } \mathrm { O } {/tex}

B

{tex} \mathrm { H } _ { 2 } \mathrm { S } {/tex}

{tex} \mathrm { NH } _ { 3 } {/tex}

D

{tex} \mathrm { PH } _ { 3 } {/tex}.

Explanation


Q 9.    

Correct4

Incorrect-1

Which one of the following is an amphoteric oxide?

{tex} \mathrm { ZnO } {/tex}

B

{tex} \mathrm { Na } _ { 2 } \mathrm { O } {/tex}

C

{tex} \mathrm { SO } _ { 2 } {/tex}

D

{tex}\mathrm B _ { 2 }\mathrm O _ { 3 } {/tex}.

Explanation



Q 10.    

Correct4

Incorrect-1

Concentrated hydrochloric acid when kept in open air sometimes produces a cloud of white fumes. The explanation for it is that

A

concentrated hydrochloric acid emits strongly smelling {tex}\mathrm{HCl}{/tex} gas all the time

B

oxygen in air reacts with the emitted {tex}\mathrm{HCl}{/tex} gas to form a cloud of chlorine gas

strong affinity of {tex}\mathrm{HCl}{/tex} gas for moisture in air results in forming of droplets of liquid solution which appears like a cloudy smoke

D

due to strong affinity for water, concentrated hydrochloric acid pulls moisture of air towards itself. This moisture forms droplets of water and hence the cloud.

Explanation


Q 11.    

Correct4

Incorrect-1

What may be expected to happen when phosphine gas is mixed with chlorine gas?

A

The mixture only cools down

B

{tex} \mathrm { PCl } _ { 3 } {/tex} and {tex} \mathrm { HCl } {/tex} are formed and the mixture warms up

{tex} \mathrm { PCl } _ { 5 } {/tex} and {tex} \mathrm { HCl } {/tex} are formed and the mixture cools down

D

{tex} \mathrm { PH } _ { 3 }.\mathrm { Cl } _ { 2 } {/tex} is formed with warming up.

Explanation


Q 12.    

Correct4

Incorrect-1

The states of hybridisation of boron and oxygen atoms in boric acid {tex} \left( \mathrm { H_3 } \mathrm { BO } _ { 3 } \right) {/tex} are respectively

A

{tex} s p ^ { 2 } {/tex} and {tex} s p ^ { 2 } {/tex}

{tex} s p ^ { 2 } {/tex} and {tex} s p ^ { 3 } {/tex}

C

{tex} s p ^ { 3 } {/tex} and {tex} s p ^ { 2 } {/tex}

D

{tex} s p ^ { 3 } {/tex} and {tex} s p ^ { 3 } {/tex}.

Explanation

Q 13.    

Correct4

Incorrect-1

In a hydrogen-oxygen fuel cell, combustion of hydrogen occurs to

A

generate heat

create potential difference between the two electrodes

C

produce high purity water

D

remove adsorbed oxygen from electrode surface.

Explanation


Q 14.    

Correct4

Incorrect-1

Which one of the following statements regarding helium is incorrect?

It is used to fill gas in balloons instead of hydrogen because it is lighter and noninflammable.

B

It is used as a cryogenic agent for carrying out experiments at low temperatures.

C

It is used to produce and sustain powerful superconducting magnets.

D

It is used in gas-cooled nuclear reactors.

Explanation


Q 15.    

Correct4

Incorrect-1

The molecular shapes of {tex} \mathrm { SF } _ { \mathrm { 4 } } , \mathrm { CF } _ { 4 } {/tex} and {tex} \mathrm { XeF } _ { 4 } {/tex} are

A

the same with {tex} 2,0 {/tex} and {tex}\mathrm{1}{/tex} lone pairs of electrons on the central atom respectively.

B

the same with {tex} 1,1 {/tex} and {tex}\mathrm{1}{/tex} lone pair of electrons on the central atoms respectively.

C

different with {tex} 0,1 {/tex} and {tex}\mathrm{2}{/tex} lone pairs of electrons on the central atom respectively.

different with {tex} 1,0 {/tex} and {tex} 2 {/tex} lone pairs of electrons on the central atom respectively.

Explanation



Q 16.    

Correct4

Incorrect-1

The number of hydrogen atom(s) attached to phosphorus atom in hypophosphorous acid is

A

{tex} \mathrm { Zero} {/tex}

{tex} \mathrm { two } {/tex}

C

{tex} \mathrm { one} {/tex}

D

{tex} \mathrm { three} {/tex}

Explanation



Q 17.    

Correct4

Incorrect-1

The correct order of the thermal stability of hydrogen halides {tex} ( \mathrm { H } - X ) {/tex} is

A

{tex} \mathrm { HI } > \mathrm { HBr } > \mathrm { HCl } > \mathrm { HF } {/tex}

{tex} \mathrm { HF } > \mathrm { HCl } > \mathrm { HBr } > \mathrm { HI } {/tex}

C

{tex} \mathrm { HCl } < \mathrm { HF } > \mathrm { HBr } < \mathrm { HI } {/tex}

D

{tex} \mathrm { HI } > \mathrm { HCl } < \mathrm { HF } > \mathrm { HBr } {/tex}

Explanation


Q 18.    

Correct4

Incorrect-1

In silicon dioxide

each silicon atom is surrounded by four oxygen atoms and each oxygen atom is bonded to two silicon atoms

B

each silicon atom is surrounded by two oxygen atoms and each oxygen atom is bonded to two silicon atoms

C

silicon atom is bonded to two oxygen atoms

D

there are double bonds between silicon and oxygen atoms

Explanation


Q 19.    

Correct4

Incorrect-1

Which of the following statements is true?

A

{tex} \mathrm { H } _ { 3 } \mathrm { PO } _ { 3 } {/tex} is a stronger acid than {tex} \mathrm { H } _ { 2 } \mathrm { SO } _ { 3 } {/tex}

B

In aqueous medium {tex}\mathrm{HF}{/tex} is a stronger acid than {tex} \mathrm { HCl } {/tex}

C

{tex} \mathrm { HClO } _ { 4 } {/tex} is a weaker acid than {tex}\mathrm{HClO}_3{/tex}

{tex} \mathrm { HNO } _ { 3 } {/tex} is a stronger acid than {tex} \mathrm { HNO } _ { 2 } {/tex}.

Explanation



Q 20.    

Correct4

Incorrect-1

The stability of dihalides of {tex}\mathrm{Si}{/tex}, {tex}\mathrm{Ge}{/tex}, {tex}\mathrm{Sn}{/tex} and {tex}\mathrm{Pb}{/tex} increases steadily in the sequence

A

{tex} \mathrm { Pb } X _ { 2 } \ll \mathrm { Sn } X _ { 2 } \ll \mathrm { Ge } X _ { 2 } \ll \mathrm { Si } X _ { 2 } {/tex}

B

{tex} \mathrm { Ge } X _ { 2 } \ll \mathrm { Si } X _ { 2 } \ll \mathrm { Sn } X _ { 2 } \ll \mathrm { Pb } X _ { 2 } {/tex}

{tex} \mathrm { Si } X _ { 2 } \ll \mathrm { Ge } X _ { 2 } \ll \mathrm { Pb } X _ { 2 } \ll \mathrm { Sn } X _ { 2 } {/tex}

D

{tex} \mathrm { Si } X _ { 2 } \ll \mathrm { Ge } X _ { 2 } \ll \mathrm { Sn } X _ { 2 } \ll \mathrm { Pb } X _ { 2 } {/tex}.

Explanation


Q 21.    

Correct4

Incorrect-1

Identify the incorrect statement among the following.

A

{tex}\mathrm {Br}_2{/tex} reacts with hot and strong {tex} \mathrm {NaOH} {/tex} solution to give {tex} \mathrm {NaBr} {/tex} and {tex} \mathrm { H } _ { 2 } \mathrm { O } {/tex}.

B

Ozone reacts with {tex} \mathrm { SO } _ { 2 } {/tex} to give {tex} \mathrm { SO } _ { 3 } {/tex}.

C

Silicon reacts with {tex} \mathrm { NaOH } _ { ( a q ) } {/tex} in the presence of air to give {tex} \mathrm { Na } _ { 2 } \mathrm { SiO } _ { 3 } {/tex} and {tex} \mathrm { H } _ { 2 } \mathrm { O } {/tex}.

{tex} \mathrm { Cl } _ { 2 } {/tex} reacts with excess of {tex} \mathrm { NH } _ { 3 } {/tex} to give {tex} \mathrm { N } _ { 2 } {/tex} and {tex} \mathrm { HCl } {/tex}.

Explanation


Q 22.    

Correct4

Incorrect-1

Regular use of the following fertilizers increases the acidity of soil?

Ammonium sulphate

B

Potassium nitrate

C

Urea

D

Superphosphate of lime.

Explanation


Q 23.    

Correct4

Incorrect-1

In context with the industrial preparation of hydrogen from water gas {tex} \left( \mathrm { CO } + \mathrm { H } _ { 2 } \right) , {/tex} which of the following is the correct statement?

{tex} \mathrm { CO} {/tex} is oxidised to {tex} \mathrm { CO } _ { 2 } {/tex} with steam in the presence of a catalyst followed by absorption of {tex} \mathrm { CO } _ { 2 } {/tex} in alkali

B

{tex}\mathrm { CO}{/tex} and {tex} \mathrm { H } _ { 2 } {/tex} are fractionally separated using differences in their densities

C

{tex}\mathrm{CO}{/tex} is removed by absorption in aqueous {tex} \mathrm { Cu } _ { 2 } \mathrm { Cl } _ { 2 } {/tex} solution

D

{tex} \mathrm { H } _ { 2 } {/tex} is removed through occlusion with {tex} \mathrm { Pd } {/tex}

Explanation


Q 24.    

Correct4

Incorrect-1

Among the following substituted silanes the one which will give rise to cross linked silicone polymer on hydrolysis is

A

{tex} \mathrm { R } _ { 3 } \mathrm { SiCl } {/tex}

B

{tex}\mathrm R _ { 4 }\mathrm S \mathrm i {/tex}

{tex} \mathrm { RSiCl } _ { 3 } {/tex}

D

{tex} \mathrm { R } _ { 2 } \mathrm { SiCl } _ { 2 } {/tex}

Explanation




Q 25.    

Correct4

Incorrect-1

In {tex} \mathrm { XeF } _ { 2 } , \mathrm { XeF } _ { 4 } , \mathrm { XeF } _ { 6 } {/tex} the number of lone pairs on {tex} \mathrm { Xe } {/tex} are respectively

A

{tex} 2,\ 3, \ 1 {/tex}

B

{tex} 1,\ 2, \ 3 {/tex}

C

{tex} 4, \ 1, \ 2 {/tex}

{tex} 3, \ 2, \ 1 {/tex}.

Explanation