Question

What do you mean by liquification of gases ?

Answer 1

Heya @user
Here is your answer
____________________________

A. On increasing the pressure gas can be easily liquefied because intermolecular attraction between gaseous molecule increases.

B. On decreasing the temperature kinetic energy of gaseous molecules decreases that's why gas can be easily liquefied

C. Temperature of gas must be lower than critical temperature.(Critical temperature - the temperature above which gas connect be liquefied whatever pressure is applied is called critical temperature)

_____________________________

Hope helped !!