Why does Ammonia liquify?
Any gas will liquefy under the right conditions of temperature and pressure. Hydrogen and Oxygen WILL liquefy if Compressed to their Critical Pressure and Cooled to their Critical Temperature. Critical Pressure and Temperature. Hydrogen: = 13.0atm and -240°C. Oxygen: = 50 atm and -119°C. At 1.0atm, Hydrogen liquid boils at -252°C. At 1.0atm, Oxygen liquid boils at -183°C. Ammonia gas simply needs to be cooled to -34°C in order to liquefy. Or, .at 55 psia (about 4.0atm), Ammonia will liquefy at 20°C. When the pressure is released to 1.0atm, the liquid NH3 will come down to its boiling point of -34°C.
