JEE Main
Chemistry
Aldehydes and Ketones
2026
JEE Main 2026 (24 January Shift 2)
JEE Main Chemistry Question (2026) — Solution
Question
Given below are two statements: Statement I : Cross aldol condensation between two different aldehydes will always produce four different products. Statement II : When semicarbazide reacts with a mixture of benzaldehyde and acetophenone under optimum pH, it forms a condensation product with acetophenone only. In the light of the above statements, choose the correct answer from the options given below
Options
- A. Statement I is false but Statement II is true
- B. Both Statement I and Statement II are false
- C. Both Statement I and Statement II are true
- D. Statement I is true but Statement II is false
Answer
B. Both Statement I and Statement II are false
Step-by-step solution
Statement I: Cross aldol condensation between two different aldehydes produces four products only if both aldehydes have -hydrogen atoms. If one aldehyde lacks -hydrogen (e.g., benzaldehyde and acetaldehyde), only two products are typically formed (one self and one cross). If neither has -hydrogen, no aldol condensation occurs. Thus, it does not 'always' produce four products. Statement I is false. Statement II: Benzaldehyde is an aldehyde and acetophenone is a ketone. Aldehydes are generally more reactive than ketones towards nucleophilic addition reactions due to less steric hindrance and greater electronic deficiency of the carbonyl carbon. Therefore, semicarbazide will react faster with benzaldehyde than with acetophenone. The statement claiming it forms a product with acetophenone only is incorrect. Statement II is false.
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Related: Chemistry — Aldehydes and Ketones · All PYQ Banks