Reaction:

The reaction involves the reaction of p-chlorotoluene with KNH2 in liquid ammonia (NH3).

Explanation:

The reaction proceeds through a nucleophilic aromatic substitution (SNAr) reaction, also known as the Benzyne mechanism.

1. Formation of Benzyne:
- The first step involves the deprotonation of p-chlorotoluene by the strong base KNH2 in liquid ammonia (NH3).
- The base abstracts a proton from the methyl group, generating a carbanion intermediate.
- The carbanion intermediate is highly unstable and undergoes an intramolecular elimination reaction, resulting in the formation of benzyne.
- Benzyne is a highly reactive intermediate that is generated by the loss of two σ-bonds in the aromatic ring.

2. Nucleophilic Attack:
- In the second step, the benzyne intermediate reacts with NH3, which acts as a nucleophile.
- The lone pair of electrons on the nitrogen atom of NH3 attacks the electrophilic benzyne intermediate.
- The nucleophilic attack leads to the formation of a new C-N bond, resulting in the substitution of the chlorine atom.
- Since the benzyne intermediate is highly reactive, the nucleophilic attack can occur at different positions on the benzene ring.

3. Major Product:
- In the case of p-chlorotoluene, the nucleophilic attack occurs at the meta position to the chlorine atom.
- This results in the formation of m-toluidine as the major product.
- The other positions on the benzene ring are less favored due to steric hindrance or electronic effects.
- Therefore, the major product of the reaction is m-toluidine.

Summary:

- The reaction of p-chlorotoluene with KNH2 in liquid NH3 proceeds through a nucleophilic aromatic substitution (SNAr) reaction.
- The reaction involves the formation of a highly reactive benzyne intermediate, which undergoes nucleophilic attack by NH3.
- Due to the electronic and steric effects, the nucleophilic attack occurs at the meta position to the chlorine atom in p-chlorotoluene.
- Therefore, the major product of the reaction is m-toluidine.