Question

Which of the following is paramagnetic with bond order $0.5$?

• A. ${{F}_{2}}$
• B. ${{H}_{2}^+}$
• C. ${{N}_{2}}$
• D. ${{O}_{2}^-}$

Answer 1

Answer: (B)

${{H}_{2}^+}$

Answer 2

$H _{2}^{+}=\sigma 1 s ^{1}$ (According to molecular orbital theory) Bond order $=\frac{\text{bonding electrons - antibonding electrons}}{2}$ $= \frac{1}{2} = 0.5$ $H_2^+$ is paramagnetic due to the presence of one unpaired electron.