(i) Loss of a proton from an amine gives RNH ‌– ion while loss of a proton from alcohol gives RO‌– ion as shown below:
R−NH2→R−NH−+H+
R−O−H→R−O−+H+
As O is more electronegative than N, RO‌– can accommodate the negative charge more easily than the RNH‌– can.
As, RO‌– is more stable than RNH‌– the former is formed more. As a result, amines are less acidic than alcohols.
(ii)(a) At boiling point, the molecules in a compound break free from their inter molecular forces and escape into the vapour phase. Weaker the inter-molecular forces, lower will be the boiling point.
(b) In 1° amines, there is strong H-bonding that bindsthe amine molecules together. Whereas in 3° amine absence of H on N atom prevents hydrogen bonding completely.
This is why 1° amines have higher boiling point.(iii) (a) The basic nature of amines is a result of the presence of l.p. of electron on the N atom. Also the electron density is increased on N due to the +I effect of alkyl group.
(b) In aryl amines the l.p. on N is involved in resonance with the benzene ring and hence less available for protonation. (c) In aliphatic amines there is no such delocalisation and hence it is morebasic.