The critical temperature of `NH_(3),CO_(2) and O_(2)` gases are 405.6K, 304.1 K and 154.2 K, respectively. If the gases are cooled from 500 K to their respective critical temperature, then which gas will be liquefied first?

Explanation

if the given gases are cooled from 500K, `NH_(3)` gets liquefied first (critical temperature 405.6K). The reason is that the critical temperature of `CO_(2) and O_(2)` are lower than that of `NH_(3)`. As a result the liquefaction of either `CO_(2)` or `O_(2)` is not possible at the critcal temperature of `NH_(3)`.