Which of the following gases has the highest critical temperature?

Critical temperatures for $A$,$B$,$C$ and $D$ gases are $25\,^{\circ}C$,$10\,^{\circ}C$,$-80\,^{\circ}C$ and $15\,^{\circ}C$ respectively. Which gas will be liquefied more easily?

Gases possess characteristic critical temperature which depends upon the magnitude of intermolecular forces between the gas particles. Critical temperatures of ammonia and carbon dioxide are $405.5 \ K$ and $304.10 \ K$ respectively. Which of these gases will liquefy first when you start cooling from $500 \ K$ to their critical temperature?

The statement that is $NOT$ correct is

At what pressure does $SO_2$ gas liquefy at room temperature?

Which are the most favorable conditions for the liquefaction of a gas?