Question

Consider the given reaction, percentage yield of : 

• A. $A>C>B$
• B. $C>A>B$
• C. $B>C>A$
• D. $C>B>A$

Hint:

Nitration of aniline is an anomaly. Usually, amino groups are $o/p$ directing, but in strong acid, the meta-isomer yield is unexpectedly high (47%) due to the formation of the anilinium ion.

Answer 1

The Correct Option is D

Step 1: Under strongly acidic nitration conditions, aniline is protonated to form the anilinium ion (\(C_6H_5NH_3^+\)).
Step 2: The \(-NH_2\) group is \(o/p\) directing, but the \(-NH_3^+\) group is meta-directing.
Step 3: This leads to a significant amount of the meta-isomer. The experimental yields are:
Para-nitroaniline (C): 51%
Meta-nitroaniline (B): 47%
Ortho-nitroaniline (A): 2%

Step 4: Therefore, the order is C (51)>B (47)>A (2).