Question

Compressibility factor for $H_2$ behaving as real gas is:

• A. 1
• B. $(1-\frac{a}{RTV})$
• C. $(1+\frac{Pb}{RT})$
• D. $\frac{RTV}{(1-a)}$

Answer 1

The correct option is C $(1+\frac{Pb}{RT})$

vander Waals equation for the real gas is given by
$(P+\frac{n^{2}a}{V^2})(V-nb)=nRT$

For $H_2$, there are no intermolecular forces and hence vander Waals constant 'a' is zero.
Hence the above equation becomes,
$P(V-nb)=nRT$
$PV-Pnb=nRT$
For 1 mole of the gas

PV = Pb + RT

$Z=\frac{PV}{RT}$
$\frac{PV}{RT}=1+\frac{Pb}{RT}$