What compound is formed when hydrogen gas is passed through nitrobenzene in the presence of finely divided nickel?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Aniline
Hydrogen with finely divided nickel reduces the nitro group to an amino group; nothing else on the ring changes.
\( \displaystyle \ce{C6H5NO2 + 3H2} \xrightarrow{\ce{Ni}} \ce{C6H5NH2 + 2H2O} \)
The –NO2 group of nitrobenzene becomes –NH2, giving aniline.
Why the other options are incorrect
Option (1) 2-Nitroaniline — Incorrect. It keeps an –NO2 group and has a second group on the ring; reduction converts the one nitro group and adds no new group.
Option (3) 4-Nitroaniline — Incorrect. For the same reason: nitrobenzene has only one nitro group, and it is the group that is reduced.
Option (4) 3-Nitroaniline — Incorrect. A nitroaniline would need two N-containing groups on the ring; the product has only the –NH2 group.
NCERT (2026-27 edition):
9.4 Preparation of Amines – “1. Reduction of nitro compounds
Nitro compounds are reduced to amines by passing hydrogen gas in the presence of finely divided nickel, palladium or platinum and also by reduction with metals in acidic medium.”