An ideal gas cannot be liquefied because ........

Explain the liquefaction of real gases and permanent gases.

The number of statements,which are correct with respect to the compression of carbon dioxide from point $(a)$ in the Andrews isotherm from the following is $..........$.
$A.$ Carbon dioxide remains as a gas up to point $(b)$
$B.$ Liquid carbon dioxide appears at point $(c)$
$C.$ Liquid and gaseous carbon dioxide coexist between points $(b)$ and $(c)$
$D.$ As the volume decreases from $(b)$ to $(c)$,the amount of liquid decreases

Explain how liquefaction can occur in different steps within the same phase using an example.

Distinguish between vapor and gas.

Critical temperature for carbon dioxide and methane are $31.1^{\circ} C$ and $-81.9^{\circ} C$ respectively. Which of these has stronger intermolecular forces and why?