Compound with both carbonyl and reducing properties

Steps:

• 2,4-DNP reagent forms a yellow precipitate with aldehydes and ketones via hydrazone formation.
• Fehling's reagent gives a red precipitate with reducing agents like aldehydes or aldoses that reduce Cu²⁺ to Cu₂O.
• Identify the option containing an aldehyde group, which tests positive for both.
• Option B (e.g., acetaldehyde) has an aldehydic -CHO group meeting both criteria.

Why B is correct:

• Aldehydes form 2,4-dinitrophenylhydrazones with 2,4-DNP and reduce Fehling's via oxidation of the aldehydic hydrogen.

Why the others are wrong:

• A (ketone like acetone): Forms DNP precipitate but does not reduce Fehling's as ketones lack aldehydic hydrogen.
• C (alcohol like ethanol): Lacks carbonyl, so no DNP reaction and not reducing for Fehling's.
• D (non-reactive like hydrocarbon): No functional groups for either test.

Final answer: B