$A$ gas deviates maximum from the ideal gas law at

In the van der Waals equation $\left( P + \frac{a}{V^2} \right)(V - b) = RT$,what do $a$ and $b$ represent?

The value of critical temperature in terms of van der Waals' constants $a$ and $b$ is given by

Under what conditions does a real gas obey the relation $PV = RT$?

Write and explain three states of matter.

$A$ fixed amount of nitrogen gas ($1$ mole) is taken and subjected to pressure and temperature variations. The experiment is performed at high pressures and various temperatures. The results obtained are shown in the figure. The correct variation of $PV/RT$ with $P$ for nitrogen gas at high temperatures will be exhibited by: