The critical temperature of ammonia and hydrogen are 405.5K and 33.2K respectively. Ammonia can be liquefied at room temperature just by compression of the gas at high pressure. Liquifaction of hydrogen , on the other hand, requires cooling as well as compression. (True/False)
True
The critical temperature of ammonia (405.5K) is well above the room temperature,so the gas at room temperature when compressed will be easily liquefied.The critical temperature of hydrogen(33.2K) on the other hand is much below than room temperature,so the gas needs to be cooled and then compressed for liquefaction.