A molecule (X) with following structure under mild acidic condition is hydrolysed to produce (Y) and (Z). Identify the correct statements about (Y) and (Z). A. Both (Y) and (Z) have same molar mass. B. (Y) and (Z) can be distinguished from each other by NaHCO_3. C. (Y) and (Z) react with HCN with same rates. D. (Y) and (Z) undergo addition reaction with 2,4-DNP. Choose the correct answer from the options given below:
D. A and D Only
Molecule (X) is an ether with two enol ether functional groups attached to the central oxygen atom. On mild acidic hydrolysis, an enol ether cleaves to give a carbonyl compound and an alcohol. The 1-propenyl side (CH_3-CH=CH-O-) hydrolyses to propanal, CH_3CH_2CHO. The isopropenyl side (-O-C(CH_3)=CH_2) hydrolyses to the enol of acetone, which tautomerises to acetone, CH_3COCH_3. Therefore, (Y) and (Z) are propanal and acetone. Statement A: Both (Y) and (Z) have the same molar mass. Propanal and acetone are functional isomers with the same molecular formula C_3H_6O and hence the same molar mass (58 g mol ^ -1 ). Statement A is true. Statement B: (Y) and (Z) can be distinguished by NaHCO_3. NaHCO_3 reacts only with carboxylic acids (releasing CO_2). Neither an aldehyde nor a ketone reacts with NaHCO_3, so it cannot distinguish between them. Statement B is false. Statement C: (Y) and (Z) react with HCN at the same rate. In nucleophilic addition to carbonyls, aldehydes react faster than ketones due to lower steric hindrance and a more electrophilic carbonyl carbon (fewer +I alkyl groups). So propanal reacts faster than acetone. Statement C is false. Statement D: (Y) and (Z) undergo addition reaction with 2,4-DNP. Both aldehydes and ketones react with 2,4-DNP (Brady's reagent) by nucleophilic addition followed by loss of water to give coloured 2,4-dinitrophenylhydrazone precipitates. Statement D is true. Hence, the correct statements are A and D only, which corresponds to option (4).
Related: Chemistry — Alcohols Phenols and Ethers · All PYQ Banks