AIIMS2018Chemistry-Molecular Orbital Theory
AIIMS 2018 Chemistry Bond Order MCQ Question
Type: MCQ-conceptual-Medium-Class 11
Which pair of diatomic species do not have same bond order?
A
B₂⁻, C₂
B
O₂²⁻, F₂⁻
C
N₂⁺, O₂⁻
D
B₂²⁻, C₂
Correct Answer
Option A
Detailed Explanation
B₂⁻ has a bond order of 1.5, while C₂ has a bond order of 2, as calculated from their molecular orbital configurations (B₂⁻: σ(1s)²σ*(1s)²σ(2s)²σ*(2s)²σ(2p)² and C₂: σ(1s)²σ*(1s)²σ(2s)²σ*(2s)²σ(2p)²π(2p)²). This difference in bond order makes option A the correct choice. In contrast, the other options either consist of species with the same bond order or have negligible differences, such as O₂²⁻ and F₂⁻, both having bond orders of 1 and 1, respectively.
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