Question

The correct decreasing order of boiling points among amines and their corresponding acids and alcohols is
(a) R – CH2 NH2 > RCOOH > RCH2OH
(b) RCH2NH2 > RCH2OH > RCOOH
(c) R – CH2OH > R – CH2NH2 > RCOOH
(d) R – COOH > R – CH2OH > R – CH2NH2

Answer 1

Answer:

Options D is correct answer of this question

Answer 2

Answer:

The correct decreasing order of boiling points of amines, acids, and carboxylic acid is  (d) $R-COOH > R-CH_{2}OH > R-CH_{2}NH_2$

Explanation:

• Amines have lower boiling points than alcohols and acids. This is due to the electronegativity of Nitrogen being lesser than that of oxygen.

• As a result, the N-H bond in amines is less polar than the O-H bond and the hydrogen bond in amines is weaker than the hydrogen bond in alcohols

Hence the boiling point of amines is lower than those of alcohols and acids of comparable molecular masses.

• The carboxylic acids have higher boiling points than alcohols due to the more extensive association of carboxylic acid molecules through hydrogen bonding.
• The hydrogen bond formed by carboxylic acid is stronger than those of alcohol.

So the decreasing order of boiling points among amines and their corresponding acid and alcohol is as follows:

             $R-COOH > R-CH_2OH > R-CH_2NH_2$