When does a gas deviate the most from its ideal behaviour?

$A$ certain quantity of real gas occupies a volume of $0.15 \ dm^3$ at $100 \ atm$ and $500 \ K$ when its compressibility factor is $1.07$. Its volume at $300 \ atm$ and $300 \ K$ (when its compressibility factor is $1.4$) is $........ \times 10^{-4} \ dm^3$ (Nearest integer).

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

At $300 \ K$,one mole of a gas present in a $10 \ L$ flask exerted a pressure of $2.706 \ atm$. What is its compressibility factor $(Z)$? (Given $R=0.082 \ L \ atm \ mol^{-1} \ K^{-1}$).

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

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?