Hydrogen bonding plays a central role in which of the following phenomena?

Options

A. Ice floats in water
B. Higher Lewis basicity of primary amines than
tertiary amines in aqueous solution
C. Formic acid is more acidic than acetic acid
D. Dimerisation of acetic acid in benzene

Answer

A, B, D

Explanation

(a) Density of ice is less than that of water due to
cage-like structure on account of hydrogen bonding
with other `H_(2)O` molecular . Hence ,ice floats on water
(b) `R-NH_(2) +H-OHharr R-overset(+)underset((I))(NH_(3))+OH^(-)`
`R_(3)N +H-OHharr R_(3)-overset(+)underset((II))(NH)+OH^(-)`
Cation (I) is more stabilised through hydrogen
bonding than cation (II). Hence ,`R-NH_(2)` is stronger
base than `R_(3) N` in aqueous solution .
(c) HCOOH is stronger acid than `CH_(3)COOH`due
to inductive effect and not due to hydrogen bonding .
(d) Acetic acid dimerises in benzene through
intermolecular hydrogen bonding