The Van der Waals equation reduces itself to the ideal gas equation at

What is the volume of $1 \ mole$ of a real gas at $STP$ $(V_{ideal} = 22.4 \ dm^3)$,if the compressibility factor of the real gas is $1.1$ at $STP$ (in $dm^3$)?

The van der Waals constants for $HCl$ gas are $a = 3.6 \ atm \ L^2 \ mol^{-2}$ and $b = 40 \ mL \ mol^{-1}$. The critical temperature of the gas is : ............. $K$ [ $R = 0.08 \ atm \ L \ K^{-1} \ mol^{-1}$ ]

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

$CH_4$ 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 $R = 0.08 \ L \ atm \ K^{-1} \ mol^{-1}$]

What is the value of $Z$ for an ideal gas and a real gas?