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 $dm^3$)?

Under what conditions do real gases behave as ideal gases?

Assertion : Greater the value of van der Waal's constant $a$,greater is the liquefaction of gas.
Reason : $a$ indirectly measures the magnitude of attractive forces between the molecules.

What is Boyle's temperature? Give its relation with the value of $Z$.

The Van der Waals parameters for gases $W$,$X$,$Y$,and $Z$ are given below. Which one of these gases has the highest critical temperature?

$Gas$	$a \ (atm \ L^2 \ mol^{-2})$	$b \ (L \ mol^{-1})$
$W$	$4.0$	$0.027$
$X$	$8.0$	$0.030$
$Y$	$6.0$	$0.032$
$Z$	$12.0$	$0.027$

For the following gases,the values of $'a'$ (van der Waals constant) are given in parentheses: $CH_4 (2.25)$,$N_2 (1.35)$,$O_2 (1.36)$,and $CO (1.46)$. Which gas will be the most difficult to liquefy?