During the World War I, Germany was dependent on sodium nitrate deposits in Chile for the nitrogen-containing compounds needed to make explosives. Seeking to free Germany from dependence on Chile, a German chemist named Fritz Haber examined the direct combination reaction between nitrogen and hydrogen, a reaction that forms ammonia.
If we decrease the concentration of ammonia in the system, this decreased concentration of ammonia is a stress externally applied to the above system. According to LeChatelier's Principle the system will favor the process that replaces the ammonia that we siphoned off. The forward reaction or process produces ammonia. On other hand, if we increase the concentration of Nitrogen that would be a stress. The system will have to respond in order to undo the stress of increased Hydrogen. …