Question

Which from following conditions defines the critical temperature of a gas is the temperature

• A. above which gas cannot be liquified by increasing pressure.
• B. above which gas can no longer remain in the gaseous state.
• C. at which volume of given mass of a gas becomes zero.
• D. at which volume of given mass of a gas becomes double.

Hint:

Critical temperature is the limit above which pressure alone cannot liquefy the gas.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept
Critical temperature \(T_c\) is the highest temperature at which a gas can be liquefied by applying pressure.

Step 2: Analysing the statements
Above \(T_c\) the kinetic energy of molecules is too high for intermolecular attraction to hold them as a liquid, however large the pressure.
A gas still exists as a gas at lower temperatures, and its volume never becomes zero or double at this point.

Step 3: Compare the options
The statement that matches is that above this temperature the gas cannot be liquefied by increasing pressure.

Final Answer:
Above the critical temperature a gas cannot be liquefied by raising the pressure. \[ \boxed{\text{(A) }\text{above which gas cannot be liquified by increasing pressure.}} \]