Question

Aryl halides are extremely less reactive towards nucleophilic substitution reactions. Give any two reasons.

Answer 1

Aryl halides are extremely less reactive towards nucleophilic substitution reactions. This is due to following reasons

1) Conjugation between the lone pair of electrons (on halogen atom ) and pi electrons ( of benzene ring).

2) Double bond character of $C-X$ bond due to resonance.

3) The C atom of $C-X$ bond is $s{p}^2$ hybridised which results in greater s character and shorter bond length. $C-X$ bond is stronger and its cleavage requires greater energy.