# Anhydrous ammonia vapor-liquid equilibrium

I have been given a anhydrous ammonia vapor liquid system in an air-tight container where the pressure is 30 bar and the temperature is 30 degrees. They claim the system is in equilibrium, which I have two doubts about.

1. The vapor pressure for anhydrous ammonia at 30 degrees is less than 30 bar, how is it possible to have this pressure in the given system?
2. Will the volume ratio of vapor phase with regards to liquid phase affect equilibrium? If so, then how?
• What's so special about 30 bar? You can have this pressure in a closed system just as well as you can have any other pressure. – Ivan Neretin Aug 9 '17 at 14:54
• @IvanNeretin the problem is not with pressure, but with the state being in equilibrium. I assumed if you have 30 bar pressure, system's temperature will change to make '30' as the saturated pressure – avz2611 Aug 9 '17 at 15:24
• Well, yeah, something will change, that's for sure. If the vapor pressure of liquid ammonia is less than 30 bar, then some of it will condense until the pressure lowers down. – Ivan Neretin Aug 9 '17 at 15:31
• So how do i deal with the question (it is for assignment purposes), because it is said system is in equilibrium, i am rather confused regarding the same. Is the question wrong? – avz2611 Aug 9 '17 at 15:37