Consider the following figure. Which of the following gases show negative as well as positive deviation from the ideal gas behaviour?

At relatively high pressure,the van der Waals equation reduces to

For real gases,the relation between $P$,$V$ and $T$ is given by the van der Waals equation,$(P + \frac{an^2}{V^2})(V - nb) = nRT$. For the following gases $CH_4, CO_2, O_2, H_2$,which gas will have $(i)$ highest value of $'a'$ $(ii)$ lowest value of $'b'$?

For which of the following gases will the van der Waals constant $'a'$ have the highest value?

Gases deviate from ideal gas behavior because the molecules $...$

$A$ real gas would be most likely to obey the ideal gas laws at