Question

A gas can be liquified by:
(A) Cooling
(B) Compressing
(C) Both a and b
(D) None of these

Answer 1

Hint: Liquification of gases is defined as the conversion of gas into liquid state as the intermolecular force of attraction increases in such a way that they combine to form liquid state.

Complete answer step-by-step:
> Liquified gas is defined as a gas which is converted into liquid form by compressing or cooling it.
> There are two conditions by which we can liquefy gases which are given below;
(1) By lowering the temperature
(2) By applying high pressure
- By lowering the temperature:- We can simply covert gases into liquid by cooling the gas molecules. At very low temperature, gases are converted into liquids.
- Boiling point:- The temperature at which the vapour pressure is equal to the atmospheric pressure of a liquid.
- By applying high pressure:- There is an intermolecular space present in between the gas molecules, so, when we compress the particles by applying pressure, intermolecular forces will increase and inter-molecular space will decrease so that it will condense into a liquid.
Hence, we can say that a gas can be liquified by both cooling and compressing. therefore option (C) is correct answer

Additional Information: Many gases can be converted into liquid by simply cooling and hence, the phase transition takes place.
Liquefaction is also used for analyzing the fundamental properties like intermolecular forces.
The temperature at which a gas must be cooled before it can liquefy by compression is called Inversion temperature.

Note: The possibility for the mistake is that this can only be done at inversion temperature because compression releases heat so that it can be cooled. Also, by reversing the process (decreasing the pressure and increasing the temperature) can revert back to the original.