Question

Which of the following pair have identical bond order?

• A. CN$^{-}$ and NO$^{+}$
• B. CN$^{-}$ and O$_2^{-}$
• C. CN$^{-}$ and CN$^{+}$
• D. NO$^{+}$ and O$_2^{-}$
• E. O$_2^{-}$ and CN$^{+}$

Hint:

Isoelectronic species have same bond order.

Answer 1

The Correct Option is A

Concept:
Bond order: \[ \frac{N_b - N_a}{2} \]

Step 1: Electron count.
CN$^{-}$ and NO$^{+}$ both have 14 electrons.

Step 2: Conclusion.
Same electronic configuration $\Rightarrow$ same bond order.