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

Option 3: m-Nitroaniline

When aniline reacts with concentrated HNO₃ and concentrated H₂SO₄ at 298 K, it undergoes nitration. However, due to the presence of the amino group (-NH₂), which is a strongly activating and ortho/para-directing group, unexpected products are formed.

Here's a breakdown of the reaction:

• Aniline reacts with the acidic medium (H₂SO₄) to form the anilinium ion (C₆H₅NH₃⁺).
• The anilinium ion is a meta-directing group, making the meta-product the major product.
• However, at lower temperatures, significant amounts of ortho and para products are also formed.
• The reaction is complex due to the protonation of the amino group, which deactivates and meta-directs the ring.

The product distribution at 298 K is approximately:

• 47% m-nitroaniline
• 51% p-nitroaniline
• 2% o-nitroaniline

Therefore, the major product is m-nitroaniline, which accounts for 47% of the product.

The correct answer is:

Option 3: m-Nitroaniline