(i) Aniline does not undergo Friedel Crafts reaction (alkylation and acetylation) due to salt formation with aluminium chloride, the lewis acid, which is used as a catalyst. Due to this, nitrogen of aniline acquires positive charge and hence acts as a strong deactivating group for further reaction.
(ii) Aromatic primary amines cannot be prepared by this method because aryl halide do not undergo nucleophilic substitution with the anion formed by phthalimide.
(iii) Due to the electron pushing nature of alkyl group, it (R) pushes electron towards nitrogen and thus makes the unshared electron pair more available for sharing with the proton of the acid. Moreover, the substituted ammonium ion formed from the amine gets stabilized due to dispersal of the positive charge by the +I effect of the alkyl group. Hence the alkyl amine are stronger base than ammonia
