The temperature below which a gas cannot exist is called ...............

Gases possess characteristic critical temperature which depends upon the magnitude of intermolecular forces between the particles. Following are the critical temperatures of some gases:

$Gases$	$Critical \ temperature \ in \ Kelvin$
$P$	$33.2$
$Q$	$5.3$
$R$	$154.3$
$S$	$126$

From the above data,what would be the order of liquefaction of these gases? Start writing the order from the gas liquefying first.

What is meant by the vapor of a substance like $CO_2$?

At what point does surface tension vanish?

Which of the following statements is incorrect?

Explain the liquefaction of $CO_2$ gas using the Thomas Andrews plot,including the effects of temperature and pressure,and define the critical constants.