Answer: NH2NH2 and KOH in ethylene glycol.
- A Zn(Hg) amalgam and concentrated HCl (Clemmensen conditions)
- B NH2NH2 and KOH in ethylene glycol
- C LiAlH4 dissolved in anhydrous ether
- D NaBH4 dissolved in ethanol
Correct answer: B. NH2NH2 and KOH in ethylene glycol
Explanation: Wolf-Kishner reduction uses hydrazine and base (KOH) at high temperature to reduce C=O to -CH2-.
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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