Question

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

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

Answer 1

Answer: (A)

Low temperature and high pressure is required

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.