Ammonolysis of Alkyl halides followed by the treatment with NaOH solution can be used to prepare primary, secondary and tertiary amines. The purpose of NaOH in the reaction is.

In the ammonolysis of alkyl halides, the alkyl halide reacts with ammonia to form an alkylammonium halide salt. For example, $$R-X + NH_3 \rightarrow R-NH_3^+X^-$$.

The product is an ammonium salt, not the free amine. The ammonium salt is formed because $$HX$$ (the hydrogen halide produced during the reaction) protonates the amine. To liberate the free amine from this salt, a strong base such as $$NaOH$$ is added.

The $$NaOH$$ neutralises the acid ($$HX$$) present in the salt: $$R-NH_3^+X^- + NaOH \rightarrow R-NH_2 + NaX + H_2O$$. This effectively removes the acidic impurity (hydrogen halide) and releases the free amine.

Therefore, the purpose of $$NaOH$$ in this reaction is to remove acidic impurities.