Among the gases $a$,$b$,$c$,$d$,$e$ and $f$,the gases that show only positive deviation from ideal behavior at all pressures in the graph are

Compressibility factor,$Z$,of a gas is given as $Z = \frac{pV}{nRT}$.
$(i)$ What is the value of $Z$ for an ideal gas?
$(ii)$ For a real gas,what will be the effect on the value of $Z$ above Boyle's temperature?

$CH_4$ gas is behaving non-ideally. The compressibility factor for the gas is $1.5$ at $2 \ atm$ and $400 \ K$. Calculate the molar volume for the gas in $litre$. [Given $R = 0.08 \ L \ atm \ K^{-1} \ mol^{-1}$]

When does the graph of $p \propto \frac{1}{V}$ not result in a straight line?

Under which conditions will a real gas behave most like an ideal gas?

At low pressure,the Van der Waals equation is reduced to: