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MHT CET202611 April 2026Evening ShiftChemistryAldehydes and KetonesActual

When ethanal and propanal undergo aldol condensation with dilute NaOH, the pair of products obtained by cross condensation reaction is

Options

  1. Abut-2-enal and 2-methylpent-2-enal
  2. Bbut-2-enal and pent-2-enal
  3. C2-methylbut-2-enal and pent-2-enal
  4. D2-methylbut-2-enal and 2-methylpent-2-enal

Correct answer

C. 2-methylbut-2-enal and pent-2-enal

Step-by-step solution

Ethanal is CH₃CHO and propanal is CH₃CH₂CHO . Cross aldol condensation occurs when the enolate ion of one aldehyde attacks the carbonyl carbon of the other aldehyde. Case 1: Enolate of ethanal attacks propanal. CH₃CH₂CHO + CH₃CHO OH^- CH₃CH₂CH(OH)CH₂CHO CH₃CH₂CH=CHCHO The product formed is pent-2-enal. Case 2: Enolate of propanal attacks ethanal. CH₃CHO + CH₃CH₂CHO OH^- CH₃CH(OH)CH(CH₃)CHO CH₃CH=C(CH₃)CHO The product formed is 2-methylbut-2-enal. Thus, the pair of products obtained by cross condensation is 2-methyl

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