Question

Which of the following phenomena is/are affected by hydrogen bonding?

• A. Ice floats in water
• B. Higher lewis basicity of primary amines than tertiary amines in aqueous solutions
• C. Formic acid is more acidic than acetic acid
• D. Dimerization of acetic acid in benzene

Answer 1

Answer: (A), (B), (D)

Dimerization of acetic acid in benzene

(a) Ice is less dense than water due to open crystal strucutre because of H-bonding.

(b) The basicity of primary amines is more than tertiary amines as after they donate lone pair to $H^{+}$, they can form H-bonding with $H_{2}O$ molecules and get easily stabilized by solvation, whereas in tertiary amines, the stabilization by solvation is very less.

(c) Formic acid is more acidic than acetic acid due to electron donating nature of $C{H}_3$ in acetic acid. The $C{H}_3$ actually contributes electron density towards the $O-H$ bond, making it harder to remove the $H^{+}$, and making acetic acid a weaker acid than formic acid.

(d) The dimerization of acetic acid in benzene is due to hydrogen bonding.