See image — Practical Organic Chemistry and Purification Chemistry Question

💡 Solution & Explanation

Concept: Acetal (P) is CH3-CH(OEt)2, which upon acid hydrolysis (H3O+) gives acetaldehyde (CH3CHO) and ethanol. Compound Q is diethyl ether (CH3CH2-O-CH2CH3), which does not hydrolyze under mild acidic conditions to give an aldehyde. Step 1 - Acid hydrolysis: When treated with H3O+, acetal P hydrolyzes to give acetaldehyde (CH3CHO) and ethanol. Diethyl ether Q does not hydrolyze under these conditions and remains unchanged. Step 2 - Na test: The hydrolysis of P produces ethanol, which reacts with Na to evolve H2 gas. Q (diethyl ether) does not produce an alcohol under mild conditions and does not react appreciably with Na to give H2. So H3O+ followed by Na can differentiate them. Step 3 - Tollens' test: The acetaldehyde produced from hydrolysis of P gives a silver mirror with Tollens' reagent (it is an aldehyde). Q yields no aldehyde, so no silver mirror. Thus H3O+ followed by Tollens' test differentiates them. Step 4 - Fehling's test: Acetaldehyde produced from P reduces Fehling's solution (aliphatic aldehyde), giving a brick-red precipitate of Cu2O. Q gives no aldehyde, so no brick-red precipitate. Thus H3O+ followed by Fehling's test also differentiates them. Since all three methods (H3O+/Na, H3O+/Tollens', H3O+/Fehling) can individually differentiate P from Q, option (d) All of these is correct. Therefore, the correct answer is D.