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JEE Main20265 April 2026Evening ShiftChemistryAldehydes and KetonesActual

Given below are two statements: Statement-I: The condensation reaction between CH₃-CH=O and under optimum pH will produce . Statement-II: The molecule will generate Ph-CH=O in the presence of dilute acid. In the light of the above statements, choose the correct answer from the options given below:

Options

  1. ABoth Statement I and Statement II are true
  2. BBoth Statement I and Statement II are false
  3. CStatement I is true but Statement II is false
  4. DStatement I is false but Statement II is true

Correct answer

D. Statement I is false but Statement II is true

Step-by-step solution

In Statement-I, evaluating the structure of semicarbazide ( H ₂ N - NH - C (= O )- NH ₂ ), the lone pair of electrons on the - NH ₂ group directly attached to the carbonyl carbon is delocalized due to resonance. The terminal - NH ₂ group of the hydrazine part is not involved in resonance with the carbonyl group, making it significantly more nucleophilic. Therefore, the condensation reaction of acetaldehyde with semicarbazide under optimum pH occurs at the terminal - NH ₂ group to yield acetaldehyde semicarbazone: C

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