Real Gas vs Ideal Gas: Compressibility Ratio

[101nancyma]

The compressibility ratio of a gas is PV/nRT. What happen to the compressibility ratio if the attration force between the gas molecules increase? The answer says it decreases because the more molecules interact with each other, so the pressure they exert on the container decreases, thus compressibility ratio decreases. The part I don't understand is according to the real gas equation, real volume increases, and real pressure decreases. If it is true, then shouldn't the compressibility ration remain the same?

 

[Electrocuted]

You must note that though what you have thought is true, you have forgotten that when there is a change (delta) in the pressure and volume, you have to take into account the temperature change as well.