Assertion: A gas can be easily liquefied at any temperature below is critical temperature.
Reason: Liquification of a gas takes place when the average kinetic energy of the molecules is low.

Options

A. When its unversion temperature equals the Boyle's temperature
B. under reversible adiabatic expansion
C. under pressure when it is cooled below the critical temperature
D. at low pressure and above critical temperature

Answer

B, C

Explanation

(i) Reversible adiabatic expansion lower the temperature hence facilitates the liquefaction of gas (ii) A gas can be liquefied below the critical temperature by increasing the pressure