Question

How aniline is obtained from nitrobenzene?

Answer 1

The aniline can be prepared from nitrobenzene by using a metal catalyst in acidic solution. This reaction is known as catalytic hydrogenation as hydrogen is inserted to a compound carrying a double or triple bond.

Complete step by step answer:
The aniline is a weak base with chemical formula ${C_6}{H_5}N{H_2}$. It is an aromatic compound where the amino group is the functional group. In aniline the amino group is attached to the aromatic ring. The aniline reacting with mineral acid gives salt. When aniline is treated with nitrous acid in acidic conditions it gets converted to diazonium salt which is used for the preparation of dyes.
Aniline can be obtained from nitrobenzene by catalytic hydrogenation of nitro benzene in acidic condition. The nitro benzene consists of a nitro group attached to the benzene ring.
The catalytic hydrogenation is defined as the reaction where the hydrogen is added to the compound carrying double bond or triple bond in the presence of a catalyst.
The reaction for the preparation of aniline from nitrobenzene is shown below.
${C_6}{H_5}N{O_2}\xrightarrow{{Sn/HCl}}{C_6}{H_5}N{H_2}$
In this reaction, nitrobenzene is reacted with tin in presence of hydrochloric acid to give aniline. Here, in this reaction tin is the catalyst.
In this reaction reduction is also taking place as the nitro group is reduced to the amino group.

Additional information:
The catalysts are those substances which do not interfere in the reaction but help to increase the rate of reaction.

Note:
Apart from the tin metal, zinc metal can also be used during the catalytic hydrogenation of nitrobenzene to aniline. The hydrochloric acid used should be concentrated.