$NH_3$ has a much higher boiling point than $PH_3$ because

Viscosity of a liquid arises due to strong intermolecular forces existing between the molecules. Stronger the intermolecular forces,greater is the viscosity. Name the intermolecular forces existing in the following liquids and arrange them in the increasing order of their viscosities. Also give reason for the assigned order in one line.
Water,hexane $(CH_3CH_2CH_2CH_2CH_2CH_3)$,glycerine $(CH_2OHCH(OH)CH_2OH)$

Unlike other hydrogen halides,hydrogen fluoride is a liquid because..........

Hydrogen bonding is maximum in

Hydrogen bonding plays a central role in the following phenomena:
$(A)$ 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.
$(D)$ Dimerisation of acetic acid in benzene.

Between ethanol and water,which one has higher viscosity and why?