Selective reaction of carbonyl compounds Steps:

• 2,4-Dinitrophenylhydrazine (DNPH) reacts with aldehydes and ketones via nucleophilic addition to form hydrazones, but not with carboxylic acids or alcohols.
• Tollens' reagent oxidizes aldehydes to carboxylic acids, giving a silver mirror, but does not react with ketones, carboxylic acids, or alcohols.
• Analyze functional groups: A (carboxylic acid), B (aldehyde), C (ketone), D (alcohol).
• Select the compound with a ketone group, which fits both criteria.

Why C is correct:

• CH3COCH3 (acetone) contains a ketone carbonyl (C=O) that forms a hydrazone with DNPH but resists oxidation by Tollens' due to lack of alpha-hydrogen for enolization.

Why the others are wrong:

• A: CH3COOH (carboxylic acid) lacks reactive carbonyl for DNPH hydrazone formation.
• B: CH3CHO (aldehyde) reacts with both DNPH and Tollens' (oxidized to acid).
• D: CH3CH2OH (alcohol) has no carbonyl, so reacts with neither reagent.

Final answer: C