Q3 / 160 · WBJEE 2012 · Chemistry

The paramagnetic behaviour of $\mathrm{B}_{2}$ is due to the presence of

  • Correct answer
    A
    two unpaired electrons in $\pi^{*}$ MO
  • B
    two unpaired electrons in $\pi$ MO
  • C
    two unpaired electrons in $\dot{\sigma}$ MO
  • D
    two unpaired electrons in $\sigma^{*}$ MO

Solution

$B_{2}=5+5=10 e^{-}$ $$ =\sigma 1 s^{2} \dot{\sigma} 1 s^{2}, \sigma 2 s^{2} \dot{\sigma} 2 s^{2}, \pi 2 p_{x}^{1}, \pi 2 p_{y}^{\prime} $$ Due to the presence of 2 unpaired electrons, in $\pi$ bonding orbitals, $B_{2}$ shows paramagnetic behaviour.

Hence, the correct answer is option: 'A'.

Relevant Questions