(i) Loss of proton from an amine gives an amide ion while loss of a proton from alcohol give an alkoxide ion.
\(\begin{aligned}
&\mathrm{R}-\mathrm{NH}_2 \longrightarrow \mathrm{R}-\mathrm{NH}^{-}+\mathrm{H}^{+} \\
&\mathrm{R}-\mathrm{O}-\mathrm{H} \longrightarrow \mathrm{R}-\mathrm{O}^{-}+\mathrm{H}^{+}
\end{aligned}\)
Since \(\mathrm{O}\) is more electronegative than \(\mathrm{N}\), so it will attract positive species more strongly in comparison to \(\mathrm{N}^{-}\). Thus, \(\mathrm{RO}^{-}\) is more stable than \(\mathrm{RNH}^{\ominus}\). Thus, alcohols are more acidic than amines. Conversely, amines are less acidic than alcohols.
(ii) Due to the presence of two \(\mathrm{H}\)-atoms on \(\mathrm{N}\)-atom of primary amines, they undergo extensive intermolecular H-bonding while tertiary amines due to the absence of \(\mathrm{H}\)-atom on the \(\mathrm{N}\)-atom do not undergo \(\mathrm{H}\)-bonding. As a result, primary amines have higher boiling points than tertiary amines of comparable molecular mass.
(iii) Aromatic amines are far less basic than ammonia and aliphatic amines because of following reasons:
(a) Due to resonance in aniline and other aromatic amines, the lone pair of electrons on the nitrogen atom gets delocalized over the benzene ring and thus it is less easily available for protonation. Therefore, aromatic amines are weaker bases than ammonia and aliphatic amines.
(b) Aromatic amines are more stable than corresponding protonated ion, Hence, they has very less tendency to combine with a proton to form corresponding protonated ion, and thus they are less basic.