Chemistry · p-Block Elements (Group 15-18)

JEE Main 2025 — 3 April, Morning Shift — Question 12

Given below are two statements, one is labelled as Statement I and the other is labelled as Statement II.

Statement I: The $N - N$ single bond is weaker and longer than that of $P-P$ single bond.

Statement II: Compounds of group 15 elements in +3 oxidation states readily undergo disproportionation reactions.

In the light of the above statements, choose the correct answer from the options given below :

Option A:
Statement I is false but Statement II is true
Option B:
Statement I is true but Statement II is false
Option C:
Both Statement I and Statement II are true
Option D:
Both Statement I and Statement II are false
Correct

Answer: D

Step-by-step solution

Statement I claims that the $\mathrm{N{-}N}$ single bond is weaker and longer than the $\mathrm{P{-}P}$ bond. Although the $\mathrm{N{-}N}$ bond is weaker due to lone–pair repulsion on small nitrogen atoms, it is shorter (not longer) than the $\mathrm{P{-}P}$ bond because nitrogen has a smaller covalent radius. Hence, Statement I is false.

Statement II claims that compounds of group 15 in $+3$ oxidation state readily undergo disproportionation.The tendency for disproportionation in $+3$ state decreases down the group ( $\mathrm{N > P > As > Sb > Bi}$ ) and $\mathrm{Bi(III)}$ does not disproportionate. Therefore the statement as written is not generally valid, and Statement II is also false.

Thus, both statements are false and the correct answer is Option D.

Answer key and solution verified before publishing.

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Exam: JEE Main 2025
Paper: 3 April, Morning Shift
Subject: Chemistry
Chapter: p-Block Elements (Group 15-18)
Topic: Introduction & Properties of Group 15: Nitrogen Family