The compressibility factor $(Z)$ of a gas is greater than unity at $1 \, atm$ and $273 \, K$. Therefore:

Which equation shows the correct form of the Berthelot equation?

Van der Waals equation of state is obeyed by real gases. For $n$ moles of a real gas,the expression will be

The correct increasing order of the value of van der Waals's constant $a$ for $CH_4, O_2$ and $H_2$ gases is

Consider the following table:

Gas	$a / (kPa \cdot dm^6 \cdot mol^{-2})$	$b / (dm^3 \cdot mol^{-1})$
$A$	$642.32$	$0.05196$
$B$	$155.21$	$0.04136$
$C$	$431.91$	$0.05196$
$D$	$155.21$	$0.4382$

$a$ and $b$ are van der Waals constants. The correct statement about the gases is:

For one mole of a van der Waals' gas,the compressibility factor $Z = (pV/RT)$ at a fixed volume will certainly decrease,if
[Given : $a$ and $b$ are standard parameters for van der Waals' gas]