Which of the following pairs of species has identical value of bond order?

Which of the following pairs of species has identical value of bond order?
  1. $\mathrm{NO}^{+}, \mathrm{N}_{2}$
  2. $\mathrm{CO}$ and $\mathrm{N}_{2}^{+}$
  3. $\mathrm{CN}^{-}, \mathrm{O}_{2}^{+}$
  4. $\mathrm{N}_{2}$ and $\mathrm{O}_{2}^{+}$

Solution

Valence electrons of $\mathrm{N}_{2}=10 \quad$ Electronic Configuration $(\sigma 2 \mathrm{~s})^{2}(\sigma * 2 \mathrm{~s})^{2}\left(\pi 2 \mathrm{p}_{x}ight)^{2}\left(\pi 2 \mathrm{p}_{y}ight)^{2}\left(\sigma 2 \mathrm{p}_{z}ight)^{2}$
Bond order $=(8-2) / 2=3$
Valence electrons of $\mathrm{NO}^{+}=10 \quad(\sigma 2 \mathrm{~s})^{2}(\sigma * 2 \mathrm{~s})^{2}\left(\pi 2 \mathrm{p}_{x}ight)^{2}\left(\pi 2 \mathrm{p}_{y}ight)^{2}\left(\sigma 2 \mathrm{p}_{z}ight)^{2}$
Bond order $=(8-2) / 2=3$
Valence electrons of $\mathrm{CO}=10 ; \quad$ Same as $\mathrm{NO}^{+}$
Valence electrons of $\mathrm{CN}^{-}=10 ; \quad$ Same as $\mathrm{NO}^{+}$
Valence electrons of $\mathrm{N}_{2}^{-}=11 \quad$ Bond order $=(9-2) / 2=3.5$
Valence electrons of $\mathrm{O}_{2}^{+}=11 \quad$ Electronic configuration $\quad(\sigma 2 \mathrm{~s})^{2}(\sigma * 2 \mathrm{~s})^{2}\left(\sigma 2 \mathrm{p}_{z}ight)^{2}\left(\pi 2 \mathrm{p}_{x}ight)^{2}\left(\pi 2 \mathrm{p}_{y}ight)^{2}\left(\pi^{*} 2 \mathrm{p}_{x}ight)^{1}$
Bond order $=(8-3) / 2=2.5$

Asked in: JEE-TOPICTESTS-CHEMISTRY

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