JEE Main 2021 · 25 February · evening · Single correct · +4 / −1
Correct statement about the given chemical reaction is :
- (a) -N̈H₂ group is ortho and para directive, so product (B) is not possible.
- (b) Reaction is possible and compound (B) will be the major product.
- (c) Reaction is possible and compound (A) will be major product.
- (d) The reaction will form sulphonated product instead of nitration.
Answer and solution
Answer (c) Reaction is possible and compound (A) will be major product.
Solution
Chemistry ma’am · 3 steps
In nitrating mixture, part of aniline becomes anilinium ion, so meta appears too, but para still wins.
- Free aniline. The lone pair on N pushes electron density into the ring, so free -NH₂ directs the nitro group to the ortho and para positions.
- Anilinium ion. H₂SO₄ is a strong acid, so a large part of the aniline is protonated to C₆H₅NH₃⁺. The -NH₃⁺ group has no lone pair and pulls electrons out of the ring, so it directs to the meta position. That is why (B) forms in a large amount.
Product Position of NO₂ Approximate yield (A) para 51% (B) meta 47% (C) ortho 2% - So. Nitration does happen and all three products form, but p-nitroaniline (A) is the major product. The answer is (c).
The idea to keep. Direct nitration of aniline gives about 51% para, 47% meta and 2% ortho. The big meta share comes from the anilinium ion formed in strong acid.
Answer from the NTA final answer key. Solution by PrepWiser.