Answer: Resonance with benzene ring decreases electrophilicity of carbonyl carbon.
- A Resonance with benzene ring decreases electrophilicity of carbonyl carbon
- B Its higher molecular weight slows diffusion to the nucleophile
- C The phenyl ring withdraws electrons inductively, hardening the carbon
- D Steric shielding by the bulky ortho hydrogens blocks approach
Correct answer: A. Resonance with benzene ring decreases electrophilicity of carbonyl carbon
Explanation: Conjugation with the phenyl ring delocalises the positive charge on carbonyl carbon, reducing its electrophilicity.
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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