Question

\(\text{Reaction of aniline with conc. HNO}_3 \text{ and conc. H}_2\text{SO}_4 \text{ at 298 K will produce 47\% of:}\)

• A. m-Nitroaniline
• B. o-Nitroaniline
• C. m-Nitroaniline
• D. 2,4-Dinitroaniline

Answer 1

The Correct Option is A

At 298 K, the reaction of aniline with concentrated nitric acid (\(\text{HNO}_3\)) and concentrated sulfuric acid (\(\text{H}_2\text{SO}_4\)) is a nitration of the aromatic compound. In this acidic environment, the aniline group first transforms into an anilinium ion:

\[\text{C}_6\text{H}_5\text{NH}_2 + \text{H}_2\text{SO}_4 \rightarrow \text{C}_6\text{H}_5\text{NH}_3^+ + \text{HSO}_4^-\]

This anilinium ion deactivates the aromatic ring for electrophilic attack, reducing its reactivity. The electron-withdrawing nature of the anilinium ion makes the meta position more susceptible to substitution than the ortho and para positions. Therefore, nitration primarily occurs at the meta position, yielding m-nitroaniline.

Under these conditions, the primary product of the reaction is m-nitroaniline, with 47% of the product being m-Nitroaniline.