Question

Assertion (A): Monobromination of aniline can be conveniently done by protecting the amino group by acetylation.
Reason (R): Acetylation increases the activation effect of the amino group.

• A. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
• B. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
• C. Assertion (A) is true, but Reason (R) is false.
• D. Assertion (A) is false, but Reason (R) is true.

Hint:

Acetylation lowers (not raises) the activating power of −NH₂, so the Reason is false.

Answer 1

The Correct Option is C

Concept: Look at each statement separately. The trap in this question is hidden in the word 'increases' inside the reason.

Step 1: Check the Assertion
The $\mathrm{-NH_2}$ group makes aniline so reactive that if we brominate it directly we get the tri-bromo product, not a single one. So first we protect the $\mathrm{-NH_2}$ by changing it to $\mathrm{-NHCOCH_3}$ through acetylation. This calms the ring down, and now we get a clean single (mono) bromination. So the Assertion is true.

Step 2: Check the Reason
Acetylation actually lowers the activating power of the amino group, it does not raise it. This is because the lone pair on nitrogen is now partly shared with the C=O group, so less of it is free to feed into the ring. The Reason claims acetylation 'increases' the activation, which is the opposite of the truth, so the Reason is false.

Step 3: Do they connect
The Assertion is true but the Reason is false, so they cannot form a matching pair.

Answer: Option (C), the Assertion is true but the Reason is false.