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 (CH3CH2CH2CH2CH2CH3) glycerine (CH2OHCH(OH)CH2OH)
In water and glycerine-Hydrogen bonding and dipole-dipole interactions exists as both are polar molecules.
hexane-Dispersion forces/London forces are present due to non-polar nature. there is hydrogen bonding which is stronger in case of glycerine (because of the presence of three -OH groups) than that in water, therefore the Water < glycerine
Since hexane has weakest intermolecular forces and glycerine the strongest (three OH groups) Intermolecular forces. Therefore, hexane has minimum viscosity and glycerine has maximum viscosity.
The order of intermolecular forces among the given liquids is Hexane < Water < Glycerine.