Question

Nitrobenzene combines with hydrogen in the presence of platinum to yield
(A) Aniline
(B) Benzene
(C) Toluene
(D) Azobenzene

Answer 1

Hint: The aromatic chemical known as nitrobenzene contains a nitro group inside of a benzene ring. By means of a nitration reaction, nitrobenzene can be produced from benzene. It has an almond-like scent and is a water-insoluble pale yellow oil. Greenish-yellow crystals form when it freezes. As a precursor of aniline, it is synthesised on a massive scale from benzene.

Complete Step by Step Solution:
In order to know that through the process of nitration, nitro benzene is created from benzene. By interacting with nitric acid and sulfuric acid, a nitro group can replace the hydrogen in an aromatic ring molecule. This process is represented as nitration.

(Self made)

The nitronium ion \[(N{O^{2 + }})\] is created during the nitration process, and then it undergoes an electrophilic aromatic substitution reaction with benzene. Nitric acid reacts with an acidic dehydrator, usually sulfuric acid, to produce the nitronium ion:
\[HN{O_3}\; + {\text{ }}{H^ + }\; \rightleftharpoons {\text{ }}N{O_2}^ + \; + {\text{ }}{H_2}O\]
In a strong acidic media like hydrochloric acid, tin reacts with the nitrobenzene to reduce it to aniline.
The following diagram illustrates the conversion of nitrobenzene to aniline:
\[{C_6}{H_5}N{O_2}\; + {\text{ }}3{\text{ }}{H_2}\; \to {\text{ }}{C_6}{H_5}N{H_2}\; + {\text{ }}2{\text{ }}{H_2}O\]
Aniline is a base substance that can be converted into urethane polymers, rubber compounds, insecticides, colours (especially azo dyes), explosives, and medications.
Therefore, Nitrobenzene on reduction with hydrogen in presence of platinum yields aniline.
Thus, the correct option is: (A) Aniline.

Note: It is important to remember that the carbylamine reaction is utilised to find primary amines. Isocyanide, a substance that is produced and has a strong odour, is the end result. This reaction is not produced by secondary or tertiary amines. The reaction is as following: \[RN{H_2} + CHC{l_3} + 3KOH \to RNC + 3KCl + 3{H_2}O\]