Explain the physical significance of van der Waals parameters.

Hello Student
van der waals parameter deal to correct some assumptions made by ideal gas law.
1) Ideal gas law assumes that each molecule/atom of gas is independent and it motion and behaviour is not effected by pressence of other molecules/atom. Which is not true in real case. Hence correction factor "a" is to rectify that error.

2) Ideal gas law also assumes gas particles to be of point size and having no inherent volume. Which is again not true. Hence the correction factor "b". This is very important when dealing with cases where the volume occupied by gas is comparable to the volume of molecule/atom