Q. 11.22 Answer the following questions based on the P – T phase diagram of :
(b) What happens when at atm pressure is cooled from room temperature at constant pressure?
At room temperature (27 oC) and 4 atm pressure CO2 exits in the vapour phase. The pressure 4 atm is less than the pressure at the triple point and therefore points corresponding to all temperatures and this pressure lie in the solid and vapour region. Once we start compressing CO2 from room temperature at this constant pressure CO2 turns from vapour to solid directly without going through the liquid phase.