Question

For a real gas at 25°C temperature and high pressure (99 bar) the value of the compressibility factor is 2, so the value of van der Waal's constant 'b' should be ______ × 10-2 L mol-1 (Nearest integer).
(Given R=0.083 L bar K-1 mol-1)

Answer 1

The correct answer is: 25.

For 1 mole at high pressure
P(V-b) = RT
PV-Pb = RT
$\frac{PV}{RT}$= 1+$\frac{Pb}{RT}$
Z = 1+$\frac{Pb}{RT}$
1 = $\frac{99(b)}{0.083×298}$
b = $\frac{0.083 ×298}{99}$≈0.249≈25×10-2