Question

An ideal gas obeying kinetic theory of gases can be liquefied, if :
A. Its temperature is more than critical temperature \[{T_c}\]
B. Its pressure is more than critical pressure ${P_c}$
C. Its pressure is more than Pc​ at a temperature less than \[{T_c}\] ​
D. It cannot be liquefied at any value of $P$ and $T$

Answer 1

Hint:A definition of an ideal gas is that there are no intermolecular forces present. Only as a gas can such a system exist. Any genuine system will behave like an ideal gas when the temperature and pressure are high enough to repel the intermolecular forces.

Complete step-by-step answer:Gas molecules are exceedingly small in comparison to the space between molecules, according to the kinetic theory of gases. Since the gas molecules are constantly moving randomly, they frequently collide with one another and the container walls. The gas molecules move more quickly at higher temperatures.
A system in which there are no intermolecular or interatomic forces is referred to as an ideal gas. Any real system will behave similarly to an ideal gas at the limit where the temperature is high enough to overcome attractive intermolecular interactions and the pressure is incredibly less.
 \[PV{\text{ }} = {\text{ }}nRT\]

Here, \[n\] is the number of gas moles, P is pressure, V is volume, T is temperature and $R$ is the universal gas constant.
A relationship between four variables that characterises the state of any gas is called the ideal gas equation. It is also known as the Equation of State for this reason.
Ideal gas has a very small volume and no force of attraction. It cannot, therefore, be liquefied at any $P$ or $T$ .

Option ‘D’ is correct

Note: Liquefaction can be seen as a severe departure from the ideal behaviour of a gas. When a gas is chilled to the point that its molecules no longer have enough kinetic energy to repel one another, this phenomenon takes place. Real gases have molecules that are attracted to one another, and when this attraction is amplified, the gas can become liquid.