An aromatic compound A on treatment with aqueous ammonia and heating forms compound B which on heating with `Br_(2)` and KOH forms a compound C of molecular formula `C_(6)H_(7)N`. Write the structures and IUPAC names of compounds A, B and C.

Explanation

It is given that compound C having the molecular formula `C_(6)H_(7)N` is formed by heating compound b with `Br_(2)` and KOH. This is a Hofmann bromamide degradation reaction. Therefore, compound B is an amide and compound C is an amine. The only amine having the molecular formula `C_(6)H_(7)N` is aniline `(C_(6)H_(5)NH_(2))`. Therefore, compound B (from which C is formed) must be benzamide, `(C_(6)H_(5)CONH_(2))`. Further, benzamide is formed by heating compound A with aqueous ammonia therefore, compound A must be benzoic acid `(C_(6)H_(5)COOH)`. The products formed can be explained with the help of the following reactions.