Answer: FCH 2 COOH.
- A ICH<sub>2</sub>COOH
- B BrCH<sub>2</sub>COOH
- C FCH<sub>2</sub>COOH
- D ClCH<sub>2</sub>COOH
Correct answer: C. FCH<sub>2</sub>COOH
Explanation: The most electronegative halogen, fluorine, exerts the greatest -I effect, so fluoroacetic acid is the strongest.
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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