- ✓$NO^-$
- B$NO^+$
- C$CN^-$
- D$N_2$
$NO ^{-}$contains $16$ electrons ( $7$ from nitrogen, $8$ from oxygen, add $1$ more for negative charge).
$NO ^{+}$has $14$ electrons ( $7$ from nitrogen, $8$ from oxygen, subtract $1$ for positive charge).
$CN ^{-1}$ has $14$ electrons ( $7$ from nitrogen, $6$ from carbon, add $1$ more for negative charge).
$N _2$ has $14$ electrons ( $7$ from nitrogen each).
The species containing the same number of electrons have the same bond order.
So $NO ^{-}$is the only one which has bond order different. So option $A$ is correct.
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
(A) $\mathrm{Cu}^{+} \rightarrow \mathrm{Cu}^{2+}+\mathrm{Cu}$
(B) $3 \mathrm{MnO}_4^{2-}+4 \mathrm{H}^{+} \rightarrow 2 \mathrm{MnO}_4^{-}+\mathrm{MnO}_2+2 \mathrm{H}_2 \mathrm{O}$
(C) $2 \mathrm{KMnO}_4 \rightarrow \mathrm{K}_2 \mathrm{MnO}_4+\mathrm{MnO}_2+\mathrm{O}_2$
(D) $2 \mathrm{MnO}_4^{-}+3 \mathrm{Mn}^{2+}+2 \mathrm{H}_2 \mathrm{O} \rightarrow 5 \mathrm{MnO}_2+4 \mathrm{H}^{+}$
Choose the correct answer from the options given below:

Element $-$ $IP$
