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Aldol condensation of acetaldehyde with itself in a 0.1 M NaOH solution produces a product. Which of the following is the major product?

medium MCQ 3 marks Class 12 · Chemistry · Aldehydes Ketones and Carboxylic Acids
  1. 2‑Hydroxybutanal
  2. 3‑Hydroxybutanal
  3. 3‑Hydroxypropionaldehyde
  4. 3‑Hydroxypentanal
Answer
3‑Hydroxybutanal

The correct answer is 3‑Hydroxybutanal — 5. Thus, the major product is 3‑hydroxybutanal.

Step-by-step solution

  1. 1. In base, acetaldehyde enolises to form the enolate ion.
  2. 2. The enolate attacks the carbonyl carbon of another acetaldehyde molecule.
  3. 3. This nucleophilic addition yields a β‑hydroxy aldehyde.
  4. 4. The product of self‑aldol condensation of acetaldehyde is , which is 3‑hydroxybutanal.
  5. 5. Thus, the major product is 3‑hydroxybutanal.
Common mistake: Confusing the product as 2‑hydroxybutanal or a ketone.

Concept tested: Aldol condensation mechanism

Published · How this solution was prepared and checked

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