See image — Practical Organic Chemistry and Purification Chemistry Question

💡 Solution & Explanation

Step 1 - Identify the structures. Compound (X) is 1,4-dioxane: a six-membered ring with oxygens at the 1 and 4 positions. It is a cyclic diether with no carbonyl or aldehyde functionality. Compound (Y) is 1,3-dioxane: a six-membered ring with oxygens at the 1 and 3 positions. This is a cyclic acetal (formally the acetal of malonaldehyde or a related carbonyl compound). The carbon at position 2 (between the two oxygens) is an acetal carbon (O-CH2-O unit). Step 2 - Hydrolysis with H3O+. When treated with aqueous acid (H3O+): - (X) 1,4-dioxane is a simple diether and does not hydrolyze readily under mild acidic conditions; it gives no carbonyl compound. - (Y) 1,3-dioxane is a cyclic acetal and hydrolyzes readily under acidic conditions to give a carbonyl compound (specifically, an aldehyde — malonaldehyde or a simpler aldehyde depending on the substituents, but the key point is an aldehyde/carbonyl is released). Step 3 - Option (b): H3O+, then Fehling test. After hydrolysis, (Y) gives an aldehyde which reduces Fehling's solution (brick-red precipitate of Cu2O), while (X) gives no aldehyde and does not reduce Fehling's solution. So (b) can differentiate (X) and (Y). ✓ Step 4 - Option (c): H3O+, then Na. After hydrolysis, (Y) gives an aldehyde product. However, the hydrolysis of the acetal also releases an alcohol (ethylene glycol or similar diol). Alcohols react with Na to give H2 gas. (X) after treatment with dilute H3O+ remains largely as the diether and upon treatment with Na shows little to no reaction (ethers do not react with Na). The hydrolysis product of (Y) contains hydroxyl groups (from the diol released) that react with Na to evolve H2 gas. This difference can be used to differentiate them. ✓ Step 5 - Option (a): H3O+, NaOI (iodoform test). NaOI tests for methyl ketones (CH3CO-) or secondary alcohols oxidizable to methyl ketones. The hydrolysis product of (Y) is an aldehyde (not a methyl ketone), so it would not give a positive iodoform test. This reagent cannot reliably differentiate the two compounds in a meaningful way. ✗ Step 6 - Conclusion. Both options (b) and (c) can differentiate compounds (X) and (Y) after acid hydrolysis, while option (a) cannot. Therefore, option (d) 'Both (b) and (c)' is the correct answer. Therefore, the correct answer is D.