Lesson eLearning

2‑Bromopropane is refluxed with excess aqueous NaOH. Identify the major organic product and briefly explain the reaction mechanism.

easy 2 marks Class 12 · Chemistry · Haloalkanes and Haloarenes
Answer
2‑Propanol

The correct answer is 2‑Propanol — Step 5: Deprotonation of the protonated alcohol yields 2‑propanol as the major product.

Step-by-step solution

  1. Step 1: 2‑Bromopropane is a secondary alkyl halide, so both SN1 and SN2 are possible.
  2. Step 2: In aqueous NaOH, the reaction is favoured by the formation of a relatively stable secondary carbocation (SN1).
  3. Step 3: The halide ion leaves, generating the secondary carbocation (CH3–C⁺H–CH3).
  4. Step 4: Water (present in the medium) attacks the carbocation to give a protonated alcohol.
  5. Step 5: Deprotonation of the protonated alcohol yields 2‑propanol as the major product.
Common mistake: Assuming the reaction proceeds via SN2 and giving 1‑propanol as the product

Concept tested: SN1 substitution of a secondary alkyl halide

Published · How this solution was prepared and checked

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