Give the structure of A , B and C in the following reactions. C 6 H 5 NO 2 → Fe / HCl A → 273 - 278 K HNO 2 B → C 6 H 5 OH C .

When, a nitro group is reduced it is easily converted to amino group. The reduction can be brought about by tin and hydrochloric acid or iron and hydrochloric acid or hydrogen in presence of nickel or platinum or lithium aluminium hydride. This leads to the formation of an intermediate compound called Benzene diazonium chloride. Arene diazonium salts react with electron rich (highly reactive) aromatic compounds such as phenols and amines to form brightly coloured azo compounds, Ar − N = N − Ar . This reaction is known as Coupling reaction. Azo compounds are used as dyes. Coupling takes place almost exclusively at the para position if it is unoccupied. If it is not, then coupling takes place at ortho position. Coupling with phenols occurs in basic medium ( pH 9 − 10 ) whereas, with amines it occurs in faintly acidic medium ( pH 4 – 5 ) at 273 − 278 K . C 6 H 5 NO 2 → Fe / HCl C 6 H 5 NH 2 → 273 - 278 K HNO 2 C 6 H 5 N 2 Cl → C 6 H 5 OH C 6 H 5 - N = N - C 6 H 4 OH .

Give only the equation for the synthesis of the fluorobenzene from benzene diazonium chloride.

The equation for the synthesis of the fluorobenzene from benzene diazonium chloride is as follows: When an aqueous solution of diazonium salt is treated with fluoroboric acid HBF 4 , diazonium fluoroborate gets precipitated. It is filtered and dried. When dry diazonium fluoroborate is heated, it composes of aryl fluoride and boron trifluoride. A r N 2 + Cl - + HBF 4 → ArN 2 + BF 4 - + HCl Diazonium fluoroborate Ar - N + ≡ NBF 4 → ∆ Ar - F + N 2 + BF 3 Aryl fluoride

E M B I B E

Bureau's Higher Secondary Chemistry Volume-2>Chapter 21 - Aryl Diazonium Salts>QUESTIONS>Q 2

MEDIUM

12th Odisha Board

IMPORTANT

Earn 100

How you will obtain $p -$ hydroxyazobenzene from aniline?

Important Questions on Aryl Diazonium Salts

MEDIUM

12th Odisha Board

IMPORTANT

Bureau's Higher Secondary Chemistry Volume-2>Chapter 21 - Aryl Diazonium Salts>QUESTIONS>Q 3

What is coupling reaction? Give two examples.

MEDIUM

12th Odisha Board

IMPORTANT

Bureau's Higher Secondary Chemistry Volume-2>Chapter 21 - Aryl Diazonium Salts>QUESTIONS>Q 4

How will you carry out the conversion of aniline to

m -

bromonitrobenzene?

EASY

12th Odisha Board

IMPORTANT

Bureau's Higher Secondary Chemistry Volume-2>Chapter 21 - Aryl Diazonium Salts>QUESTIONS>Q 5

Give the structure of $A, B$ and $C$ in the following reactions.

$C_{6} H_{5} {N_{2}}^{+} {Cl}^{-} \overset{CuCN}{\to} A \overset{H_{2} O / H^{+}}{\to} B \overset{{NH}_{3}}{\to} C$ .

MEDIUM

12th Odisha Board

IMPORTANT

Bureau's Higher Secondary Chemistry Volume-2>Chapter 21 - Aryl Diazonium Salts>QUESTIONS>Q 5

Give the structure of $A, B$ and $C$ in the following reactions.

$C_{6} H_{5} {NO}_{2} \overset{Fe / HCl}{\to} A \to_{273 - 278 K}^{{HNO}_{2}} B \overset{C_{6} H_{5} OH}{\to} C$ .

HARD

12th Odisha Board

IMPORTANT

Bureau's Higher Secondary Chemistry Volume-2>Chapter 21 - Aryl Diazonium Salts>QUESTIONS>Q 1

Discuss in detail the preparation of benzenediazonium chloride from aniline. Why it is not separated in solid state and used as soon as produced in solution? How can you convert benzenediazonium chloride to fluoro and iodobenzene?

HARD

12th Odisha Board

IMPORTANT

Bureau's Higher Secondary Chemistry Volume-2>Chapter 21 - Aryl Diazonium Salts>QUESTIONS>Q 2

Describe the synthetic applications of aryl diazonium salts.

MEDIUM

12th Odisha Board

IMPORTANT

Bureau's Higher Secondary Chemistry Volume-2>Chapter 21 - Aryl Diazonium Salts>QUESTIONS>Q 3

How will you obtain iodobenzene from nitrobenzene?

MEDIUM

12th Odisha Board