A hydrocarbon X having molecular formula C ₇ H ₈ undergoes chlorination in the presence of sunlight to yield an intermediate Y . Compound Y upon hydrolysis with water at 373 K gives compound Z . If Z gives a positive Tollens' test, identify the intermediate Y .

Step-by-step solution

The hydrocarbon X with molecular formula C ₇ H ₈ is toluene. Compound Z gives a positive Tollens' test, which indicates that Z is an aldehyde. Since it is derived from toluene, Z must be benzaldehyde. Benzaldehyde is prepared by the hydrolysis of a gem-dihalide. Therefore, the intermediate Y formed by the photochemical chlorination of toluene must be benzal chloride (dichloromethylbenzene). The reaction sequence is: Toluene + 2 Cl ₂ (in sunlight) Benzal chloride ( Y ) + 2 HCl Benzal chloride + H ₂ O (at 373 K ) Ben