An aromatic primary amine A with molecular formula `C_6H_7N` undergoes diazotisation to give B.B when treated with hypophosphorous acid gives C. Identify A, B and C.

Explanation

(i) An aromatic primary amine (A) is identified as aniline `C_6H_5NH_2`.
(ii) Aniline undergoes diazotisation to give benzene diazonium chloride `C_6H_5N_2Cl` and it is (B).
`{:(C_6H_5NH_2underset(0^(@) C)overset(NaNO_2+HCl)(to)C_6H_5N_2Cl),(" Aniline Benzene diazonium chloride(B) "):}`
(iii) Benzene diazonium chloride on treatment with hypophosphorous acid gives benzene `C_6H_6` and it is (C ).
`{:(C_6H_5N_2Clunderset(2[H])overset(H_3PO_2)(to)C_6H_6+N_2uparrow+HCl),(" Benzene(C ) "):}`.