Question

How does applying pressure (or compression) help in the liquefaction of a gas ?

Answer 1

We can liquefy gases either by applying pressure (compression). There is a lot of space between the particles of a gas as they have very high kinetic energy and they keep moving randomly. We reduce the spaces between the particles of a gas by compressing it. If enough pressure is applied, the particles of gases start attracting each other. This force brings about a change in the state of matter from gas to liquid.