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Question : 26
Total: 26
(a) Write the reactions involved in the following:
(i) Hoffmann bromamide degradation reaction
(ii) Diazotisation
(iii) Gabriel phthalimide synthesis
(b) Give reasons:
(i)( CH 3 ) 2 NH ( CH 3 ) 3 N
(ii) Aromatic diazonium salts are more stable than aliphatic diazonium salts.
OR
(a) Write the structures of the main products of the following reactions:
(c) Arrange the following in the increasing order of theirpK b
C 6 H 5 NH 2 , C 2 H 5 NH 2 , C 6 H 5 NHCH 3
(i) Hoffmann bromamide degradation reaction
(ii) Diazotisation
(iii) Gabriel phthalimide synthesis
(b) Give reasons:
(i)
(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
Solution:
(a) (i) Ar ∕ R − CONH 2 + Br 2 + 4 NaOH → Ar ∕ R − NH 2 + 2 NaBr + Na 2 CO 3 + 2 H 2 O
(ii)C 6 H 5 NH 2 + NaNO 2 + 2 HCI
C 6 H 5 N 2 + Cl − + NaCl + 2 H 2 O
(iii) Gabriel Pthalimide reaction:2 ∘ 3 ∘
(ii) Aromatic diazonium salts are more stable than aliphatic diazonium salts due to dispersion of positive charge over the benzene ring caused by resonance. This is not found in aliphatic diazonium salts.
(a)KOH N , N
(c)C 2 H 5 NH 2 < C 6 H 5 NHCH 3 < C 6 H 5 NH 2
(ii)
(iii) Gabriel Pthalimide reaction:
(b) (i)
(ii) Aromatic diazonium salts are more stable than aliphatic diazonium salts due to dispersion of positive charge over the benzene ring caused by resonance. This is not found in aliphatic diazonium salts.
OR
(a)
(b) Add chloroform in the presence of
(c)
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