The unsaturated ether on acidic hydrolysis produces carbonyl compounds as shown below:- aligned CH _ 3 - CH = CH - & O - CH = CH _ 2 \\ & H _ 3 O ^ (+) \\ CH _ 3 - CH _ 2 - CH = & O and O = CH - CH _ 3 aligned Based on this, predict the solution/reagent that will help to distinguish " P " and " Q " obtained in the following reaction:-
A. Fehling solution
Acidic hydrolysis of vinyl ethers involves the addition of water across the double bond followed by the elimination of alcohol/phenol to form carbonyl compounds. In the given reaction: CH_3-CH=CH-O-C(CH_3)=CH_2 H_3O^+ P + Q The hydrolysis occurs at both vinyl ether linkages. The left part CH_3-CH=CH-O- hydrolyzes to form propanal: CH_3-CH_2-CHO (P). The right part -O-C(CH_3)=CH_2 hydrolyzes to form acetone: CH_3-CO-CH_3 (Q). P is an aldehyde (propanal) and Q is a ketone (acetone). Fehling solution is used to distinguish between aldehydes and ketones. Aldehydes (except benzaldehyde) reduce Fehling solution to give a red precipitate of Cu_2O, while ketones do not react. Lucas reagent is used for alcohols. 2,4-DNP reacts with both aldehydes and ketones. Saturated NaHSO_3 reacts with most aldehydes and methyl ketones, so it is not the best choice for distinguishing these specific compounds compared to Fehling solution.
Related: Chemistry — Alcohols Phenols and Ethers · All PYQ Banks