Explanation

(b)
The first bond between any two atoms is $\sigma$ and rest are $\pi$ bonds.
$\pi$ bond is formed by sideways overlapping of unhybridised $p$-orbital.
[image:4_image136.emf]
Each carbon has 3$\sigma$ and 1 $\pi$-bond.
$\therefore$ All carbon atoms of $C_{6}H_{6}$ are $sp^{2}$ hybridised.