Aryl halides are less reactive in nucleophilic substitution reactions.

• (i) write any two reasons for less reactivity
• (ii) Give one example for nucleophilic substitution reaction of aryl halides

Aryl halides, which are compounds where a halogen atom is bonded to an aromatic ring, exhibit lower reactivity in nucleophilic substitution reactions compared to alkyl halides. This can be attributed to several factors.

Reasons for Reduced Reactivity

• Resonance Stabilization: The presence of the aromatic ring allows for resonance, which stabilizes the aryl halide. This delocalization of electrons makes the carbon-halogen bond stronger and less susceptible to nucleophilic attack.
• Hybridization: The carbon atom in aryl halides is sp² hybridized, leading to a planar structure. This configuration makes it more difficult for nucleophiles to approach and attack the carbon atom compared to sp³ hybridized carbons found in alkyl halides.

Example of Nucleophilic Substitution

One common example of a nucleophilic substitution reaction involving an aryl halide is the reaction of chlorobenzene with sodium hydroxide (NaOH) under high temperature and pressure, resulting in the formation of phenol:

Chlorobenzene + NaOH → Phenol + NaCl

This reaction typically proceeds via an aromatic nucleophilic substitution mechanism, where the nucleophile (OH^-) attacks the carbon bonded to the chlorine atom.