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MHT CET202519 Apr 2025Evening ShiftChemistryAminesActual

What is the loss in molar mass when a primary amine is obtained by Hofmann degradation of amide?

Options

  1. A32 ~g ~mol ⁻¹
  2. B14 ~g ~mol ⁻¹
  3. C28 ~g ~mol ⁻¹
  4. D30 ~g ~mol ⁻¹

Correct answer

C. 28 ~g ~mol ⁻¹

Step-by-step solution

Hofmann degradation converts primary amides to primary amines with one fewer carbon atom: R-CO-NH ₂ Br ₂, NaOH R-NH ₂ + Na ₂ CO ₃ + 2 NaBr + 2 H ₂ O The carbonyl group ( - CO - ) is lost during this transformation and appears as Na ₂ CO ₃ . Molar mass loss corresponds to the carbonyl group: 12 + 16 = 28 g mol ⁻¹ . Final answer: C

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