Question

At a temperature less than Critical temperature, to liquefy a gas:

• A. Low temperature and low pressure is required
• B. High temperature and low pressure is required
• C. Low temperature and high pressure is required
• D. None of these

Answer 1

Answer: (C)

Gases become more difficult to liquefy as the temperature increases because the kinetic energies of the particles that make up the gas also increase. The critical temperature of a substance is the temperature at and above which vapor of the substance cannot be liquefied, no matter how much pressure is applied.

At a temperature less than Critical temperature, to liquefy a gas low temperature and high pressure is required.

Hence option A is correct.