Question

Give reasons :

(i) Electrophilic substitution in aromatic amines takes place more readily than benzene.

(ii) CH₃CONH₂ is a weaker base than CH₃CH₂NH₂.

Answer 1

(i) -NH₂ group of aromatic amines strongly activates the aromatic ring through delocalization of the lone pair of electrons of the N-atom over the aromatic ring. Due to the strong activating effect of the -NH₂ group, aromatic amines undergo electrophilic substitution reactions readily than benzene.

(ii) Due to resonance, the lone pair of electrons on the nitrogen atom in CH₃CONH₂ is delocalized over the keto group.

As a result, electron density on the N-atom in CH₃CONH₂ decreases. On the other hand, in C₂H₅NH₂, due to + I effect of the ethyl group, the electron density on the N-atom increases consequently, CH₃CONH₂ is a weaker base than CH₃CH₂NH₂.

Comments

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