Question

Viscocity 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 ($CH_{3}CH_{2}CH_{2}CH_{2}CH_{2}CH_{3}$), glycerine ($CH_{2}OHCH(OH)CH_{2}OH$).

Answer 1

1. Given if the liquid has stronger intermolecular force then the viscosity of the liquid is higher. Both intermolecular force and viscosity are directly related.

2. In water intermolecular force exist with hydrogen bonding.

3. The intermolecular force that exist in n-hexane is induced by dipole-dipole forces or Van der Waal’s forces or London forces

4. The intermolecular forces that exist in glycerine are with hydrogen bonds. Hence the boiling point of the glycerine is higher.

5. The increase order is given as Hexane < Water < Glycerine