Question

a gas can be liquefied easily

Answer 1

yes it could b such as by increasing pressure and decreasing temperature.

Answer 2

hey there... .

here is ur a answer...

gases can be liquified when we increase the pressure it cool the temperature. when we increase the pressure the intermolecular space will decrease and the gas will turn to liquid form.
when we compress lquid too much heat is produced so this heat has to be removed so we need to cool it.
so lquiefing can be done by increase the pressure and when increase the pressure we need to cool it.

hope this helps!