JEE Main · 2023 · 13 Apr 2023 · Shift 1 · Chemical Bonding and Molecular Structure

In which of the following processes, the bond order increases and paramagnetic character changes to diamagnetic one?

(A) $O_{2} \to O_{2}^{2 -}$
(B) $NO \to NO^{+}$ ✓ Correct
(C) $N_{2} \to N_{2}^{+}$
(D) $O_{2} \to O_{2}^{+}$

Answer: (B)

Solution

Nitric oxide has fifteen electrons, a bond order of

2.5

and one unpaired electron, so it is paramagnetic. Removing one electron from its highest antibonding

π^{*}

orbital gives the nitrosonium ion with fourteen electrons, a bond order of

3.0

and no unpaired electrons. On going from nitric oxide to the nitrosonium ion the bond order therefore increases and the species changes from paramagnetic to diamagnetic.

JEE Main · 2023 · 13 Apr 2023 · Shift 1 · Single correct option

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