Question

Removal of electron results in increase in bond order of the bond in :-

• A. $CN$
• B. $O_2$
• C. $C_2$
• D. $N_2$

Answer 1

Answer: (B)

According to MOT, electronic configuration of $O_2$ molecules is following-
$\sigma 1s^2<{\sigma }^{\ast }1s^2<\sigma 2s^2<\sigma \ast 2s^2<$ $\sigma 2p_z^2<\pi 2p_x^2=\pi 2p_y^2<{\pi }^{\ast }2p_x^1={\pi }^{\ast }2p_y^1$
Bond order $=\frac{\text{Bonding electrons - Anti Bonding electrons}}{2}$
Removal of electron will take place from highest energy orbital.
In $O_2$ will remove electron from anti-bonding orbital, if number of anti-bonding electron decrease, bond order increase.
In rest of the options, electron will remove from bonding orbital hence it decrease their bond order.
So, option 2 is correct.