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 liquify first when you start cooling from 500 K to their critical temperature ?

Explanation

Higher the critical temperature, more easily the gas liquesfies. As `NH_(3)` has higher critical temperature, on cooling down from 500 K, the critical temperature of `NH_(3)` will be reached first. Hence, `NH_(3)` will be liquefied first `CO_(2)` will be liquefied only on further cooling.