The graph between $P$ and $V$ below the critical temperature is:

When is deviation more in the behaviour of a gas from the ideal gas equation $PV = nRT$?

For real gases,the van der Waals equation is written as $\left( p + \frac{a n^2}{V^2} \right) (V - nb) = nRT$,where $a$ and $b$ are van der Waals constants. Two sets of gases are:
$(I)$ $O_2, CO_2, H_2, He$
$(II)$ $CH_4, O_2, H_2$
The gases given in set-$I$ are arranged in increasing order of $b$,and the gases given in set-$II$ are arranged in decreasing order of $a$. Select the correct order from the following:

At $300 \ K$,the compressibility factor of $1 \ mole$ of a gas is $1.1$. Its pressure is $2.706 \ atm$. What is its volume in $L$? (Given $R=0.082 \ L \ atm \ mol^{-1} \ K^{-1}$).

The pressure of a van der Waals gas is less than the pressure of an ideal gas because of

Which of the following indicates a plot of compressibility factor $(Z)$ $vs$ $p$ at room temperature for helium?