JEE Main 2024ChemistryAminesHardNumerical

JEE Main 2024 — Amines Question with Solution

JEE Main 2024 (31 Jan Shift 2)

Question

A compound x with molar mass 108g mol−1 undergoes acetylation to give product with molar mass 192g mol−1. The number of amino groups in the compound x is ________.

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Show full solutionCorrect answer: 2
Correct answer
2

Step-by-step explanation

The compounds like amines and alcohols undergo acetylation with acetyl chloride. During this reaction, one proton of amine or alcohol is replaced with one acetyl group(CH3CO-).

The molar mass of the acetyl group is 43 g/mol. The increase in molar mass due to one acetyl group is 43-1=42g/mol.

The molar mass of reactant is 108 g/mol. The molar mass of product is 192 g/mol.  The change in mass is 84.

Hence, the number of acetyl groups =8442=2

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About this question

This is a previous-year question from JEE Main 2024, covering the Amines chapter of Chemistry. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.