Explain the physical significance of van der Waals parameters.

Explanation

Significance of constant 'b'. The constant 'b' is called co-volume or excluded volume per mole of a gas lts units are litre `mol^(-1)`. The volume of 'b' is four times the actual volume of the molecules.
Significance of constant 'a'. The value of constant 'a' given the idea of magnitude of attractive forces between the molecules of the gas. its units are atm `L^(2) mol^(-2)`. larger the value of a, larger will be the intermolecular attraction among the gas molecules.