At a temperature of $27\,^{\circ}C$,if the volume of $2\, \text{moles}$ of $NH_3$ gas is $5\, L$ according to the van der Waals equation,what will be its pressure in $atm$? ($a = 4.17$,$b = 0.03711$)

For $1 \ mol$ of gas,the plot of $pV$ vs $p$ is shown below. $p$ is the pressure and $V$ is the volume of the gas. What is the value of compressibility factor at point $A$?

Calculate the compressibility factor for $SO_2$,if $1 \ mol$ of it occupies $0.35 \ L$ at $300 \ K$ and $50 \ atm$ pressure.

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:

The density of a gas $A$ at $1 \ atm$ and $750 \ K$ is $0.3 \ g/L$. If the molar mass of $A$ is $27 \ g/mol$,then choose the correct statement -

For a real gas,what do negative and positive deviations in the $pV$ vs $p$ plot at constant temperature signify?