13.23 Give plausible explanation for each of the following:

(i) Why are amines less acidic than alcohols of comparable molecular masses?

(ii) Why do primary amines have higher boiling point than tertiary amines?

(iii) Why are aliphatic amines stronger bases than aromatic amines? 

<p><strong> (i)</strong> Aromatic amines react with nitrous acid (prepared in situ from NaNO₂and a mineral acid such as HCl) at 273 - 278 K to form stable aromatic diazonium salts e., NaCl and water.</p><p>&nbsp;</p><p><strong> (ii)</strong> Aliphatic primary amines react with nitrous acid (prepared in situ from NaNO₂and a mineral acid such as HCl) to form unstable aliphatic diazonium salts, which further producealcohola and acid called as hydrochloric acid and evolution of nitrogen</p><p>&nbsp;</p><p><strong> (iii)</strong> Aliphatic amines are stronger bases than aromatic amines due to following reasons:</p><p><strong> (a)</strong> The lone pair of electrons of the nitrogen atom of aromatic amines is involved in</p><p>conjugation with the π−bond pairs of the ring as follows</p><p><strong> (b)</strong> Anilinium ion obtained by accepting a proton is less stabilized by resonance. Due to the −R effect of the benzene ring, the electrons on the N- atom are less available in the case of aromatic amines. Therefore, the electrons on the N-atom in aromatic amines cannot be donated</p><p>So, aniline is a weaker base than alkyl amines, in which +1 effect increases the electron density on the nitrogen atom.</p>

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