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JEE Main 2025 Apr 2 Shift 1, Chemistry Q11: Properties and Important Reactions of Aldehydes & Ketones

JEE Main2025Apr 2, Shift 1Chemistry
Q.

Given below are two statements :

Statement (I) : Vanillin will react with NaOH and also with Tollen's reagent.

Statement (II) : Vanillin will undergo self aldol condensation very easily.


In the light of the above statements, choose the most appropriate answer from the options given below :

  1. A

    Statement I is incorrect but Statement II is correct

  2. B

    Statement I is correct but Statement II is incorrect

  3. C

    Both Statement I and Statement II are incorrect

  4. D

    Both Statement I and Statement II are correct

Solution

Vanillin (4-hydroxy-3-methoxybenzaldehyde) carries two reactive groups on an aromatic ring: a phenolic –OH and a –CHO.

Statement I:

(i) The phenolic –OH is acidic and dissolves in aqueous NaOH to give a sodium phenoxide. ✓

(ii) Aromatic aldehydes give the silver-mirror test with Tollens' reagent, oxidising to the corresponding carboxylic acid. ✓

Hence Statement I is correct.

Statement II: Self-aldol condensation requires an -hydrogen on the carbonyl compound to form the necessary enolate. The –CHO group of vanillin sits directly on the aromatic ring and has no -hydrogen. So vanillin cannot undergo self-aldol condensation.

Hence Statement II is incorrect.

Option (2) is correct.

Concept behind this question

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