Question

Statement-I : The correct increasing order of bond length among the following is $O_2^+ < O_2 < O_2^- < O_2^{2-}$.
Statement-II : The correct order of number of unpaired electrons is $O_2^{2-} < O_2^+ < O_2^- < O_2$.

• (1) Both Statement-I and Statement-II are correct
• (2) Statement-I is correct and Statement-II is incorrect
• (3) Statement-II is correct and Statement-I is incorrect
• (4) Both Statement-I and Statement-II are incorrect

Answer 1

The Correct Option is B

Molecular Orbital (MO) configuration of diatomic Oxygen species.

LOGIC:
1. Species and Bond Order (BO): $O_2^+ (2.5), O_2 (2.0), O_2^- (1.5), O_2^{2-} (1.0)$.
2. Since Bond Length $\propto 1/BO$, the length order is $O_2^+ < O_2 < O_2^- < O_2^{2-}$. Statement-I is TRUE.
3. Unpaired Electrons: $O_2^{2-}$ has 0, $O_2^+$ has 1, $O_2^-$ has 1, and $O_2$ has 2.
4. Statement-II implies a strict increase: $0 < 1 < 1 < 2$. Mathematically, $O_2^+ < O_2^-$ is false as they are equal. Thus, Statement-II is FALSE.
5. Result: Statement-I correct, Statement-II incorrect. Option (2).