Question

The compressibility factor for a real gas at high pressure is

• A. $1+\frac{RT}{pb}$
• B. $1$
• C. $1+\frac{pb}{RT}$
• D. $1-\frac{pb}{RT}$

Answer 1

The correct option is C

$1+\frac{pb}{RT}$

C According to van der waals we have

At high pressure $p+\frac{a^2}{V_m^2}\approx P$

Van der Waals equation for 1 mole i.e.

At high pressure b is significant Here for 1mole b=n b . Actually n b is significant at high pressures.