An ideal gas cannot be liquefied because

According to the kinetic molecular theory of gases,which of the following statements is correct for a diatomic molecule?

What type of kinetic energy do $He$ and $Ne$ possess?

According to the kinetic molecular theory of gases, which of the following statements are correct?
$a$) The actual volume of the molecules is negligible in comparison to the empty space between them.
$b$) Collisions of gas molecules are inelastic.
$c$) At any particular time, different particles in the gas have the same speed and same kinetic energies.
$d$) Pressure is exerted by the gas as a result of the collision of the particles with the walls of the container.

The average kinetic energy of one molecule of an ideal gas at $27^{\circ} C$ and $1 \ atm$ pressure is

If a gas expands at a constant temperature,then...