A gas can be liquified by pressure alone only, when its temperature is __________ its critical temperature.

A. Less than

B. More than

C. Equal to or higher than

D. Less than or equal to

Answer: Option D

Solution(By Examveda Team)

Only below and at the critical point there is strong demarcation in properties of liquids and gases above the critical point we can’t recognize the difference. Hence for a gas which is under or at the critical point can be liquefied. For a gas above critical point can also undergo a pressure change but we can’t notice the difference in properties.