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


Q 1.    

Correct4

Incorrect-1

Match the interhalogen compounds of column-I with the geometry in column-II and assign the correct code.

{tex}\mathrm{ A - (iii), B -(i), C-(iv), D -(ii)} {/tex}

B

{tex}\mathrm{ A - (v), B -(iv), C-(iii), D -(ii)} {/tex}

C

{tex}\mathrm{ A - (iv), B -(iii), C-(ii), D -(i)} {/tex}

D

{tex}\mathrm{ A - (iii), B -(iv), C-(i), D -(ii)} {/tex}

Explanation

Q 2.    

Correct4

Incorrect-1

In which pair of ions both the species contain {tex} \mathrm {S-S} {/tex} bond?

{tex} \mathrm { S } _ { 4 } \mathrm { O } _ { 6 } ^ { 2 - } , \mathrm { S } _ { 2 } \mathrm { O } _ { 3 } ^ { 2 - } {/tex}

B

{tex} \mathrm { S } _ { 2 } \mathrm { O } _ { 7 } ^ { 2 - } , \mathrm { S } _ { 2 } \mathrm { O } _ { 8 } ^ { 2 - } {/tex}

C

{tex} \mathrm { S } _ { 4 } \mathrm { O } _ { 6 } ^ { 2 - } , \mathrm { S } _ { 2 } \mathrm { O } _ { 7 } ^ { 2 - } {/tex}

D

{tex} \mathrm { S } _ { 2 } \mathrm { O } _ { 7 } ^ { 2 - } , \mathrm { S } _ { 2 } \mathrm { O } _ { 3 } ^ { 2 - } {/tex}

Explanation

Q 3.    

Correct4

Incorrect-1

Match the compounds given in column I with the hybridisation and shape given in column II and mark the correct option.

A

{tex}\mathrm{ A - (iv), B -(iii), C-(i), D -(ii)} {/tex}

B

{tex}\mathrm{ A - (iv), B -(i), C-(ii), D -(iii)} {/tex}

{tex}\mathrm{ A - (i), B -(iii), C-(iv), D -(ii)} {/tex}

D

{tex}\mathrm{ A - (i), B -(ii), C-(iv), D -(iii)} {/tex}

Explanation

Q 4.    

Correct4

Incorrect-1

Which is the correct statement for the given acids?

Phosphinic acid is a monoprotic acid while phosphonic acid is a diprotic acid.

B

Phosphinic acid is a diprotic acid while phosphonic acid is a monoprotic acid.

C

Both are diprotic acids.

D

Both are triprotic acids.

Explanation

Q 5.    

Correct4

Incorrect-1

Which one of the following orders is correct for the bond dissociation enthalpy of halogen molecules?

A

{tex} \mathrm { Br } _ { 2 } > \mathrm { I } _ { 2 } > \mathrm { F } _ { 2 } > \mathrm { Cl } _ { 2 } {/tex}

B

{tex} \mathrm { F } _ { 2 } > \mathrm { Cl } _ { 2 } > \mathrm { Br } _ { 2 } > \mathrm { I } _ { 2 } {/tex}

C

{tex}\mathrm { I _ { 2 } > B r _ { 2 } > Cl _ { 2 } > F _ { 2 } }{/tex}

{tex} \mathrm { Cl } _ { 2 } > \mathrm { Br } _ { 2 } > \mathrm { F } _ { 2 } > \mathrm { I } _ { 2 } {/tex}

Explanation

Q 6.    

Correct4

Incorrect-1

When copper is heated with conc.{tex}\mathrm { HNO_{3}}{/tex}, it produces

A

{tex} \mathrm { Cu } \left( \mathrm { NO } _ { 3 } \right) _ { 2 } , \mathrm { NO } {/tex} and {tex} \mathrm { NO } _ { 2 } {/tex}

B

{tex} \mathrm { Cu } \left( \mathrm { NO } _ { 3 } \right) _ { 2 } {/tex} and {tex} \mathrm { N } _ { 2 } \mathrm { O } {/tex}

{tex} \mathrm { Cu } \left( \mathrm { NO } _ { 3 } \right) _ { 2 } {/tex} and {tex} \mathrm { NO } _ { 2 } {/tex}

D

{tex} \mathrm { Cu } \left( \mathrm { NO } _ { 3 } \right) _ { 2 } {/tex} and {tex} \mathrm { NO } {/tex}

Explanation

Q 7.    

Correct4

Incorrect-1

Among the following, the correct order of acidity is

A

{tex} \mathrm { HClO } _ { 2 } < \mathrm { HClO } < \mathrm { HClO } _ { 3 } < \mathrm { HClO } _ { 4 } {/tex}

B

{tex} \mathrm { HClO } _ { 4 } < \mathrm { HClO } _ { 2 } < \mathrm { HClO } < \mathrm { HClO }_{3} {/tex}

C

{tex} \mathrm { HClO } _ { 3 } < \mathrm { HClO } _ { 4 } < \mathrm { HClO } _ { 2 } < \mathrm { HClO } {/tex}

{tex} \mathrm { HClO } < \mathrm { HClO } _ { 2 } < \mathrm { HClO } _ { 3 } < \mathrm { HClO } _ { 4 } {/tex}

Explanation


Q 8.    

Correct4

Incorrect-1

Strong reducing behaviour of {tex} \mathrm { H } _ { 3 } \mathrm { PO } _ { 2 } {/tex} is due to

A

high electron gain enthalpy of phosphorus

B

high oxidation state of phosphorus

C

presence of two {tex} \mathrm{- OH }{/tex} groups and one {tex} \mathrm { P } - \mathrm { H } {/tex} bond

presence of one {tex} \mathrm{- OH }{/tex} group and two {tex} \mathrm { P } - \mathrm { H } {/tex} bonds.

Explanation

Q 9.    

Correct4

Incorrect-1

The variation of the boiling points of the hydrogen halides is in the order {tex} \mathrm { HF } > \mathrm { HI } > \mathrm { HBr } > \mathrm { HCl } {/tex}
What explains the higher boiling point of hydrogen fluoride?

There is strong hydrogen bonding between HF molecules.

B

The bond energy of HF molecules is greater than in other hydrogen halides.

C

The effect of nuclear shielding is much reduced in fluorine which polarises the HF molecule.

D

The electronegativity of fluorine is much higher than for other elements in the group.

Explanation

Q 10.    

Correct4

Incorrect-1

Which of the statements given below is incorrect?

A

{tex} \mathrm { O } _ { 3 } {/tex} molecule is bent.

B

{tex} \mathrm {ONF}{/tex} is isoelectronic with {tex} \mathrm { O } _ { 2 } \mathrm { N } ^ { - } {/tex}

{tex} \mathrm { OF } _ { 2 } {/tex} is an oxide of fluorine.

D

{tex} \mathrm { Cl } _ { 2 } \mathrm { O } _ { 7 } {/tex} is an anhydride of perchloric acid.

Explanation

Q 11.    

Correct4

Incorrect-1

The formation of the oxide ion, {tex} \mathrm { O } ^ { 2 - } _{(g)} {/tex} from oxygen atom requires first an exothermic and then an endothermic step as shown below:
{tex} \mathrm { O } _ { ( g ) } + e ^ { - } \rightarrow \mathrm { O } _ { ( g ) } ^ { - } ; \Delta _ { f } H ^ { \circ } = - 141\ \mathrm { kJ }\ \mathrm { mol } ^ { - 1 } {/tex}
{tex} \mathrm { O } _ { ( \mathrm { g } ) } ^ { - } + e ^ { - } \rightarrow \mathrm { O } _ { ( \mathrm { g } ) } ^ { 2- } ; \Delta _ { f } H ^ { \circ } = + 780\ \mathrm { kJ }\ \mathrm { mol } ^ { - 1 } {/tex}
Thus, process of formation of {tex} \mathrm { O } ^ { 2 - } {/tex}in gas phase is unfavourable even though {tex} \mathrm { O } ^ { 2 - } {/tex} is isoelectronic with neon. It is due to the fact that,

A

{tex}\mathrm{O^{-}}{/tex} ion has comparatively smaller size than oxygen atom

B

oxygen is more electronegative

C

addition of electron in oxygen results in larger size of the ion

electron repulsion outweighs the stability gained by achieving noble gas configuration.

Explanation

Q 12.    

Correct4

Incorrect-1

Nitrogen dioxide and sulphur dioxide have some properties in common. Which property is shown by one of these compounds, but not by the other?

A

Is soluble in water.

Is used as a food preservative.

C

Forms 'acid-rain'.

D

Is a reducing agent.

Explanation

Q 13.    

Correct4

Incorrect-1

Acidity of diprotic acids in aqueous solutions increases in the order

{tex} \mathrm { H } _ { 2 } \mathrm { S } < \mathrm { H } _ { 2 } \mathrm { Se } < \mathrm { H } _ { 2 } \mathrm { Te } {/tex}

B

{tex} \mathrm { H } _ { 2 } \mathrm { Se } < \mathrm { H } _ { 2 } \mathrm { S } < \mathrm { H } _ { 2 } \mathrm { Te } {/tex}

C

{tex} \mathrm { H } _ { 2 } \mathrm { Te } < \mathrm { H } _ { 2 } \mathrm { S } < \mathrm { H } _ { 2 } \mathrm { Se } {/tex}

D

{tex} \mathrm { H } _ { 2 } \mathrm { Se } < \mathrm { H } _ { 2 } \mathrm { Te } < \tilde { \mathrm { H } } _ { 2 } \mathrm { S } {/tex}

Explanation

Q 14.    

Correct4

Incorrect-1

Which is the strongest acid in the following?

{tex} \mathrm { HClO } _ { 4 } {/tex}

B

{tex} \mathrm { H } _ { 2 } \mathrm { SO } _ { 3 } {/tex}

C

{tex} \mathrm { H } _ { 2 } \mathrm { SO } _ { 4 } {/tex}

D

{tex}\mathrm {HClO}{/tex}

Explanation

Q 15.    

Correct4

Incorrect-1

Which one of the following molecules contains no {tex} \pi {/tex} bond?

A

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

B

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

C

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

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

Explanation

Q 16.    

Correct4

Incorrect-1

Which of the following does not give oxygen on heating?

A

{tex} \mathrm { K } _ { 2 } \mathrm { Cr } _ { 2 } \mathrm { O } _ { 7 } {/tex}

{tex} \left( \mathrm { NH } _ { 4 } \right) _ { 2 } \mathrm { Cr } _ { 2 } \mathrm { O } _ { 7 } {/tex}

C

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

D

{tex} \mathrm { Zn } \left( \mathrm { ClO } _ { 3 } \right) _ { 2 } {/tex}

Explanation

Q 17.    

Correct4

Incorrect-1

Identify the incorrect statement, regarding the molecule {tex} \mathrm { XeO } _ { 4 } {/tex} :

{tex} \mathrm { XeO } _ { 4 } {/tex} molecule is square planar.

B

There are four {tex} p \pi - d \pi {/tex} bonds

C

There are four {tex} s p ^ { 3 } -p , \sigma {/tex} bonds.

D

{tex} \mathrm { XeO } _ { 4 } {/tex} molecule is tetrahedral.

Explanation

Q 18.    

Correct4

Incorrect-1

In which of the following compounds, nitrogen exhibits highest oxidation state?

A

{tex} \mathrm { N } _ { 2 } \mathrm { H } _ { 4 } {/tex}

B

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

{tex} \mathrm { N } _ { 3 } \mathrm { H } {/tex}

D

{tex} \mathrm { NH } _ { 2 } \mathrm { OH } {/tex}

Explanation

Q 19.    

Correct4

Incorrect-1

Which of the following statements is not valid for oxoacids of phosphorus?

A

Orthophosphoric acid is used in the manufacture of triple superphosphate.

Hypophosphorous acid is a diprotic acid.

C

All oxoacids contain tetrahedral four coordinated phosphorus.

D

All oxoacids contain atleast one {tex} \mathrm { P } = \mathrm { O } {/tex} unit and one {tex} \mathrm { P } - \mathrm { OH } {/tex} group.

Explanation

Q 20.    

Correct4

Incorrect-1

Sulphur trioxide can be obtained by which of the following reaction?

A

{tex} \mathrm { CaSO } _ { 4 } + \mathrm { C } \stackrel { \Delta } { \longrightarrow } {/tex}

{tex} \mathrm { Fe } _ { 2 } \left( \mathrm { SO } _ { 4 } \right) _ { 3 } \stackrel { \Delta } { \longrightarrow } {/tex}

C

{tex} \mathrm { S } + \mathrm { H } _ { 2 } \mathrm { SO } _ { 4 } \stackrel { \Delta } { \longrightarrow } {/tex}

D

{tex} \mathrm { H } _ { 2 } \mathrm { SO } _ { 4 } + \mathrm { PCl } _ { 5 } \stackrel { \Delta } { \longrightarrow } {/tex}

Explanation

Q 21.    

Correct4

Incorrect-1

In which of the following arrangements the given sequence is not strictly according to the property indicated against it?

A

{tex} \mathrm { HF } < \mathrm { HCl } < \mathrm { HBr } < \mathrm { HI } : {/tex} increasing acidic strength

{tex} \mathrm { H } _ { 2 } \mathrm { O } < \mathrm { H } _ { 2 } \mathrm { S } < \mathrm { H } _ { 2 } \mathrm { Se } < \mathrm { H } _ { 2 } \mathrm {Te} {/tex} : increasing {tex} \mathrm { p } K _ { a } {/tex} values

C

{tex} \mathrm { NH } _ { 3 } < \mathrm { PH } _ { 3 } < \mathrm { AsH } _ { 3 } < \mathrm { SbH } _ { 3 } : {/tex} increasing acidic character

D

{tex} \mathrm { CO } _ { 2 } < \mathrm { SiO } _ { 2 } < \mathrm { SnO } _ { 2 } < \mathrm { PbO } _ { 2 } : {/tex} increasing oxidising power

Explanation

Q 22.    

Correct4

Incorrect-1

Oxidation states of {tex} \mathrm { P } {/tex} in {tex} \mathrm { H } _ { 4 } \mathrm { P } _ { 2 } \mathrm { O } _ { 5 } , \mathrm { H } _ { 4 } \mathrm { P } _ { 2 } \mathrm { O } _ { 6 } {/tex}, {tex} \mathrm { H } _ { 4 } \mathrm { P } _ { 2 } \mathrm { O } _ { 7 } {/tex} are respectively

A

{tex} + 3 , + 5 , + 4 {/tex}

B

{tex} + 5 , + 3 , + 4 {/tex}

C

{tex} + 5 , + 4 , + 3 {/tex}

{tex} + 3 , + 4 , + 5 {/tex}

Explanation

Q 23.    

Correct4

Incorrect-1

The correct order of increasing bond angles in the following species is

A

{tex} \mathrm { Cl } _ { 2 } \mathrm { O } < \mathrm { ClO } _ { 2 } < \mathrm { ClO } _ { 2 }^{-} {/tex}

B

{tex} \mathrm { ClO } _ { 2 } < \mathrm { Cl } _ { 2 } \mathrm { O } < \mathrm { ClO } _ { 2 } ^ { - } {/tex}

C

{tex} \mathrm { Cl } _ { 2 } \mathrm { O } < \mathrm { ClO } _ { 2 } ^ { - } < \mathrm { ClO } _ { 2 } {/tex}

{tex} \mathrm { ClO } _ { 2 } ^ { - } < \mathrm { Cl } _ { 2 } \mathrm { O } < \mathrm { ClO } _ { 2 } {/tex}

Explanation

Q 24.    

Correct4

Incorrect-1

How many bridging oxygen atoms are present in {tex} \mathrm { P } _ { 4 } \mathrm { O } _ { 10 } ? {/tex}

6

B

4

C

2

D

5

Explanation

Q 25.    

Correct4

Incorrect-1

Among the following which is the strongest oxidising agent?

A

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

B

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

C

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

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

Explanation