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MHT CET202520 Apr 2025Evening ShiftChemistryAldehydes and KetonesActual

Identify the product ' B ' in following reaction. Ethanal dil NaOH ~A [- H ₂ O ] B

Options

  1. A3-Hydroxybutanal
  2. B4-Hydroxybutanal
  3. CBut-2-enal
  4. DBut-3-enal

Correct answer

C. But-2-enal

Step-by-step solution

Ethanal contains -hydrogens and undergoes aldol condensation under dilute NaOH. Two molecules react via aldol addition to form 3-hydroxybutanal: 2CH₃ CHO [dil NaOH] CH₃ CH(OH)CH₂ CHO Upon heating, this -hydroxy aldehyde dehydrates to form the , -unsaturated aldehyde but-2-enal: CH₃ CH(OH)CH₂ CHO [ ][-H₂ O] CH₃ CH=CHCHO The product sequence yields 3-hydroxybutanal (A) followed by but-2-enal (B). Among the options, but-2-enal corresponds to option C. Final answer: C

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