Chlorobenzene is extremely less reactive towards a nucleophilic substitution reaction. Give two reasons for the same.

Chlorobenzene is less reactive towards nucleophilic substitution reaction.

1. In chlorobenzene the lone pair of electrons on the halogen atom is delocalized on the benzene ring. These are stabilized by resonance, hence, the energy of activation for displacement of halogen is much greater than alkyl halides.
2. In chlorobenzene, the carbon atom to which the halogen atom is attached is sp2 hybridized and highly electronegative in nature so it cannot be replaced by a nucleophile.