An organic compoud [A] which has characteristic odour on treatment with `NaOH` forms two compounds [B] and [C]. Compounds [B] has the molecule formula `C_(7)H_(8)O`. Which on oxidation gives back compound [A]-The compound [C] is the sodium salt of an acid [C]. When [C] is heated with sodalime, it yield an aromatic hydrocarbon [D]. Deduce the structures of [A], [B], [C] and [D].

Explanation

The organic compound [A] is an aromatic aldehyde i.e., bezaldehyde with a characteristic smell. When benzaldehyde is treated with NaOH. It undergoes cannizzaro's reaction to form benzyl alcohol [B] with formula `C_(7)H_(8)O` and sodium salt of benzoic acid [C]. Benyl alcohol upon oxidation gives back benzaldehyde [A]. The compound [C] upon heating with soda lime gives an armatic hydrocarbon [D] which is benzene. The enters series of reaction is as given :