Methyl chloride on treatment with excess of ammonia yields

Mixture of methylamine, dimethylamine and trimethylamine

The correct answer is Option (4) → Mixture of methylamine, dimethylamine and trimethylamine

Methyl chloride (CH₃Cl) undergoes nucleophilic substitution (SN2) with ammonia (NH₃). Ammonia acts as a nucleophile and attacks the carbon, displacing Cl⁻ to form methylamine (CH₃NH₂).

However, methylamine is also a nucleophile (stronger than ammonia due to the +I effect of the methyl group) and can further react with additional CH₃Cl to form dimethylamine ((CH₃)₂NH), which can then react to form trimethylamine ((CH₃)₃N).

Since excess ammonia is used, the primary amine (methylamine) predominates, but secondary and tertiary amines are also formed as side products. Quaternary ammonium salt formation is minimal under these conditions.

Thus, the reaction yields a mixture of methylamine, dimethylamine, and trimethylamine. To obtain a specific amine selectively, different methods (e.g., Gabriel synthesis for primary) are used.