The compressibility factor for a real gas at high pressure is (OJEE 2012) (a) RT Pb

The Van der Waals equation can be written as- 2 2 ( / )( ) P n a V V nb nRT For, n=1 2 ( / )( ) P a V V b RT At very high pressure, 2 / a V is neglected Therefore, ( )( ) P V b RT / 1 / PV RT Pb RT Also, / PV RT z (z is the compressibility factor) 1 / z Pb RT