Which intermolecular force is most responsible for allowing $Xe$ gas to liquefy?

Isotherms of carbon dioxide gas are shown in the figure. Mark a path for changing gas into liquid such that only one phase (i.e.,either a gas or a liquid) exists at any time during the change. Explain how the temperature,volume,and pressure should be changed to carry out this process.

Distinguish between vapor and gas.

Which among the following gases is difficult to liquefy?

Explain the liquefaction of real gases and permanent gases.

What will be the phase of $CO_2$ at critical pressure $P_C$ and temperatures of $13.1^{\circ}C$,$31.5^{\circ}C$,$50^{\circ}C$,and $30.98^{\circ}C$?