Answer: One molecule of aldehyde acts as the hydride donor and gets oxidised.
- A One molecule of aldehyde acts as the hydride donor and gets oxidised
- B The aqueous solvent is oxidised to release hydrogen gas as frequently described
- C Hydroxide ion is reduced after attacking the carbonyl carbon in most textbook accounts
- D The alcohol product is re-oxidised back to aldehyde during normal conditions
Correct answer: A. One molecule of aldehyde acts as the hydride donor and gets oxidised
Explanation: In the Cannizzaro mechanism, one aldehyde molecule transfers a hydride and gets oxidised to carboxylate while the other is reduced to alcohol.
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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