Question

Gas $A$ can be liquefied at room temperature by applying pressure but gas $B$ cannot. This reflects.
A. Critical temperature of B less than that of A.
B. Critical temperature of B is greater than that of A.
C. A and B have a critical temperature greater than room temperature.
D. Critical temperatures of both are equal.

Answer 1

Hint:Before answering the question let us first talk about critical temperature. No matter how much pressure is applied, a material cannot exist as a liquid at the temperature described above. A critical temperature exists for any material. The pressure needed to liquefy a material vapour at its critical temperature is known as the critical pressure.

Complete answer:
The force of attraction between molecules is represented by the critical temperature. The intermolecular force of attraction increases as the critical temperature rises, making liquefaction of the gas simpler.So in the above mentioned question, at room temperature, gas A can be liquefied by applying pressure.

As a result, gas A's critical temperature is higher than room temperature.However, applying pressure to gas B does not cause it to liquefy at room temperature. As a result, gas B's critical temperature is lower than room temperature. This indicates that B's critical temperature is lower than A's.

So the correct answer is option A.

Note:Now the question can arise as to what occurs at a critical point? The vapour pressure rises as the temperature rises, and the gas phase becomes denser. The liquid expands and becomes less dense until the densities of liquid and vapour are equal at the critical stage, reducing the boundary between the two phases.