Anorganic compound with molecular formula `C_9H_10O` forms 2,4-DNP derivative, reduces Tollens' reagent and undergoes Cannizzaro reaction. On vigorous oxidation, it gives 1,2-benzenedicarboxylic acid. Identify the compound.

Explanation

(i) Since the given compound with M.F. `C_9H_10O` forms a 2,4-DNP derivative, therefore, it is an aldehyde or ketone.
(ii) Since it reduces Tollens. reagent, it must be an aldehyde.
(iii) Since it undergoes Cannizzaro.s reaction, so it does not contain any a-hydrogen. It suggests that CHO group is directly attached to the benzene ring.
(iv) On vigorous oxidation, it gives 1,2-benzene- dicarboxylic acid, therefore, it must be having an alkyl group at o-position with respect to -CHO group.
(v) The molecular formula suggests that it should be 2-ethylbenzaldehyde,

All the reactions can now be explained on the basis of this structure as follows: