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A compound with molecular mass 180 is acylated with CH3COCl to get a compound with molecular mass 390. The number of amino groups present per molecule of the former compound is -

1. 4
2. 6
3. 2
4. 5

Correct answer: 5

Solution

The increase in molecular mass from 180 to 390 indicates that 210 mass units are added during acylation. Since the acylation of an amino group with CH3COCl adds 42 mass units per amino group, dividing 210 by 42 gives 5, indicating there are 5 amino groups in the original compound.

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