Question

How does pressure help in liquification of gas?

Answer 1

if pressure is increased then molecules of the kinetic energy decreases and gas comes closer therefore gases are liquified

Answer 2

     High pressure compresses the gas into a smaller volume.  The temperature may decrease.  The molecules come closer to each other.  The molecules get attracted to each other due to inter molecular attraction forces.  Since the mobility and the vibrations get reduced, the kinetic energy reduces.  The number of intermolecular collisions increases.  The mean free path reduces.  The temperature reduces.

   So the gas gets liquefied at a higher temperature than at 1 atmospheric pressure.