Why does not ammo0nolysis of alkyl halides yield pure amines?

(A) Ammonolysis of alkyl halides is not a suitable method for the preparation of pure primary amines. (R) Ammonolysis of alkyl halides yields mainly secondary amines.

Why ammonolysis of alkyl halide not a suitable method for the preparation of primary amine?

Why are alkyl halides insoluble in water?