Which carbonyl compound reduces Fehling's solution to give a brick-red precipitate of Cuprous oxide (Cu2O)?
Answer and explanation
Correct answer: A. Acetaldehyde (Ethanal)
- Step 1: Fehling's solution is a mild alkaline reagent containing Cu2+ complexed with tartrate that oxidizes aliphatic aldehydes. Step 2. Acetaldehyde easily reduces Cu2+ to a brick-red precipitate of Cu2O, whereas ketones cannot be oxidized by Fehling's solution. Answer: Acetaldehyde (Ethanal). Why not the others: Acetone is a ketone (negative); benzophenone is an aromatic ketone; acetophenone is a ketone.
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