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

Give plausible explanation for each of the following: (i) Why are ami

1.	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 points than tertiary amines? (iii) Why are aliphatic amines stronger bases than aromatic amines?
Answer» Solution :(i) LOSS of a proton from an amine gives an amide ion while loss of a proton from alcohol gives an alkoxide ion as shown below: `underset("Amide")(R-NH_(2))tounderset("Amide ion")(R-NH^(-))+H^(+)` `R-O-H to R-O^(-)+H^(+)` Since O is more electronegative than N, therefore, `RO^(-)` can accommodate the -ve charge more easily than the `RNH^(-)` can accommodate the negative charge. In other WORDS, `RO^(-)` is more stable than `RNH^(-)`. thus, ALCOHOLS are more acidic than amines. conversely, amines are less acidic than alchols. (ii). Due to the PRESENCE of two H-atoms on N-atom of primary amines, they undergo extensive intermolecular H-bonding while tertiary amines due to the absence of a H-atom on the N-atom on the N-atom, do not undergo H-bonding. as a result, primary amines have HIGHER boiling points than tertiary amines of comparable molecular masses. for example, boiling points of n-butylamine (b.p. 351 K) is much higher than that of tert-butylamine (b.p. 319K)