The correct option is D Higher Lewis basicity of primary amines than tertiary amines in aqueous solutions
(a) Density of ice is less than water due to cage-like structure, in which each water molecule is surrounded by four other water molecules tetrahedrally through H- bonding. Hence, ice floats in water.
(b) RNH21o amine+H−OH⇌RNH+3I+OH−R3−N3o amine+H−OH⇌R3NH+II+OH−
The cation (I) is more stabilised through hydrogen bonding than cation (II). So, R−NH2 is stronger base than R3N in aqueous solution.
(c) HCOOH is stronger acid than CH3COOH due to inductive effect and not due to hydrogen bonding.
(d) Acetic acid dimerises in benzene through intermolecular hydrogen bonding.