Question

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 \[\ce{(CH3CH2CH2CH2CH2CH3), glycerine (CH2OH CH(OH) CH2OH)}\]

Answer 1

Hexane is a nonpolar molecule which has london force between the molecules, which is a weak force. 

Water and glycerine have \[\ce{O}\] atoms which is an electronegative atom that forms \[\ce{H}\] bonding between the molecules along with dipole-dipole interaction.. 

Glycerine has three \[\ce{O}\] atoms, so it forms more \[\ce{H}\] bonding and hence, has stronger intermolecular forces.

So the increasing order of intermolecular forces is Hexane < Water < Glycerin. Stronger the intermolecular forces, the greater is the viscosity, so the increasing order of their viscosities is: 

Hexane < Water < Glycerin