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JEE MainChemistryAldehydes and Ketones

An , -unsaturated carbonyl compound X ( C ₁₀ H ₁₀ O ) undergoes 1,4-conjugate addition with NaCN followed by acidic hydrolysis to yield compound Y ( C ₁₁ H ₁₂ O ₃ ). Compound Y is formed as a racemic mixture, gives a yellow precipitate with I ₂/ NaOH , and produces effervescence with aqueous NaHCO ₃ . Identify the two starting materials that undergo cross-aldol condensation to synthesize compound X.

Options

  1. ABenzaldehyde and Acetone
  2. BAcetophenone and Acetaldehyde
  3. CBenzaldehyde and Propanal
  4. DPhenylacetaldehyde and Acetaldehyde

Correct answer

A. Benzaldehyde and Acetone

Step-by-step solution

Compound Y gives effervescence with aqueous NaHCO ₃ , indicating the presence of a carboxylic acid ( - COOH ) group, which is formed by the hydrolysis of the - CN group added via 1,4-conjugate addition. Compound Y gives a yellow precipitate with I ₂/ NaOH (positive iodoform test), indicating the presence of a methyl ketone ( - CO - CH ₃ ) group. Since Y is formed by the 1,4-addition of cyanide to X followed by hydrolysis, X must be an , -unsaturated methyl ketone with the molecular formula C ₁₀ H ₁₀ O . Let us eval

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