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JEE Main 2025 Jan 28 Shift 1, Chemistry Q4: Properties of Amines

JEE Main2025Jan 28, Shift 1Chemistry
Q.

Given below are two statements :

Statement I : The compound will undergo alkaline hydrolysis at a faster rate than

Statement II : In intramolecular substitution takes place first by involving lone pair of electrons on nitrogen.

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

  1. A

    Both Statement I and Statement II are incorrect

  2. B

    Statement I is incorrect but statement II is correct

  3. C

    Both Statement I and Statement II are correct

  4. D

    Statement I is correct but Statement II is incorrect

Solution

In the first substrate the nitrogen lone pair is two carbons away from the C-Cl bond. Nitrogen attacks the carbon bearing chloride from the back, displacing Cl to form a strained three-membered aziridinium (cyclic ammonium) intermediate. This neighbouring-group participation, called anchimeric assistance, is intramolecular and therefore very fast.

cyclic aziridinium

The second substrate has only a carbon framework with no internal nucleophile, so it must rely on direct attack by hydroxide, which is slower.

Both the rate ordering (Statement I) and the explanation via intramolecular substitution by the nitrogen lone pair (Statement II) are correct.

Both statements are correct.

Concept behind this question

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