Question

According to MOT,$ C_2$ molecule has

• A. one $\sigma$ and one $\pi$-bond.
• B. only two $\pi-bonds.$
• C. only two $\sigma - bonds.$
• D. one $\sigma$ and two $\pi$ bonds.

Answer 1

Answer: (B)

$C_2(12)=\sigma 1s^2, \sigma^* 1s^2, \sigma 2s^2, \sigma^* 2s^2, \pi 2p^2_x \approx\pi 2p^2_y$
$C_2$ has two pairs of electrons in $\pi2p_x\, and\, \pi2p_y$ therefore, it has only two $\pi$-bonds.