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

Chlorobenzene is extremely less reactive towards a nucleophilic substitution reaction. This is due to:-

(i) Resonance effect- Due to resonance, the electron pair on chlorine atom is in conjugation with the electrons of the benzene ring which results in the following resonating structures

Resonance structures of chlorobenzene

Due to delocalization of electrons, a partial double bond character develops in the C-Cl bond, which makes it difficult for the nucleophile to cleave the C-Cl bond.

(ii) Due to repulsion from the increased electron density on the benzene ring, the nucleophile finds it difficult to attack on the molecule.