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🧪 Chemistry  ·  Aldehydes, Ketones and Carboxylic Acids  ·  NEET & JEE

The reaction of acetaldehyde with ammonia gives paraldehyde by:

Answer: Trimerisation.

  • A Trimerisation
  • B Dimerisation
  • C Polymerisation
  • D Cannizzaro reaction

Correct answer: A. Trimerisation

Explanation: Acetaldehyde undergoes trimerisation with traces of acid catalyst to form paraldehyde.

Nucleophilic Addition to C=ONu:-CORR'CO-RR'Nu

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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