Answer: 3-Hydroxybutanal (aldol product).
- A 3-Hydroxybutanal (aldol product)
- B Crotonaldehyde formed directly without an aldol intermediate
- C Sodium acetate via the Cannizzaro pathway
- D Ethanol via Meerwein-Ponndorf-Verley reduction
Correct answer: A. 3-Hydroxybutanal (aldol product)
Explanation: Aldol condensation with dilute base gives 3-hydroxybutanal (the aldol product) without dehydration.
Curved arrows show the nucleophile attacking the carbonyl carbon while the C=O pi electrons move onto oxygen, giving a tetrahedral alkoxide intermediate.
Concept context
Aldehydes, ketones, carboxylic acids, and their derivatives (esters, amides, acid chlorides). Key reactions include nucleophilic addition, Aldol condensation, Cannizzaro, and Claisen. Very heavily tested in JEE and NEET.
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