Question

Aryl halides are less reactive towards nucleophilic substitution reaction as compared to alkyl halides due to:

• A. formation of a less stable carbonium ion in aryl halides
• B. resonance stabilisation in aryl halide
• C. presence o fdouble bonds in alkyl halides
• D. inductive effect in aryl halides

Answer 1

Answer: (B)

resonance stabilisation in aryl halide

In aryl halides, the reactivity of nucleophilic substitution reactions depends upon several factors such as the nature of leaving group, bond dissociation enthalpy of $C-X$ bond, a solvent used. Whereas for alkyl halides carbon atoms to which halogen is attached is $s{p}^3$ hybridized and hence lowers the dissociation enthalpy. Therefore due to resonance stabilization in aryl halide aryl halides are less reactive.