Chapter 12: Amines

Important Questions

1. Arrange the following compounds in an increasing order of their solubility in water:
C₆H₅NH₂, (C₂H₅)₂NH, C₂H₅NH₂

2. Write the structure of 2-aminotoluene.

3. Account for the following:
(i) Primary amines (R − NH )₂ have higher boiling point than tertiary amines R N 3 ( )
(ii) Aniline does not undergo Friedel-Crafts reaction.
(iii) (CH₃)₂NH is more basic than (CH₃)₂ in an aqueous solution.

4. State reasons for the following:
(i) pK_b value for aniline is more than that for methylamine.
(ii) Ethylamine is soluble in water whereas aniline is not soluble in water.
(iii) Primary amines have higher boiling points than tertiary amines.

5. (a) Explain why an alkylamine is more basic than ammonia?
(b) How would you convert?
(i) Aniline to nitrobenzene
(ii) Aniline to iodobenzene

Sample Questions

1. Write chemical equations for the following conversions:
(i) Nitrobenzene to benzoic acid.
(ii) Benzyl chloride to 2-phenylethanamine
(iii) Aniline to benzyl alcohol

2. (a) Write the reactions involved in the following:
(i) Hofmann bromamide degradation reaction
(ii) Diazotisation
(iii) Gabriel phthalamide synthesis
(b) Give reasons:
(i) (CH₆)2NH is more basic than (CH₃)₃N in an aqueous solution.
(ii) Aromatic diazonium salts are more stable than aliphatic diazonium salts.
OR
(a) Write the structures of the main products of the following reactions:

(b) Give a simple chemical test to distinguish between Aniline and N,N-dimethylaniline.
(c) Arrange the following in the increasing order of their pKb values:
C₆H₅NH₂,C₂H₅NH₂, C₆H₅NHCH₃