What are the most favourble conditions to liquefy a gas ?

It is possible to liquefy a gas

What are the general conditions for liquification of a gas?

Assertion: Andrews worked on a temporary gas (so called at that time) and derived the condition to liquefy the permanent gases (so called at that time). Reason: Andrews studied isotherms of CO_(2) and obtained the required conditions of liquefaction of gas as T gas lt Tc (critical temperature).

What are the necessary conditions for a substance to be a Gas?

Which set of conditions represents easiest way to liquefy a gas ?

Which set of conditions represents easiest way to liquefy a gas ?