Experiment 4.12: Ammonia Fountain
An inverted round-bottomed flask filled with ammonia gas is connected by a glass tube to a reservoir of water (with phenolphtalein).
Water rushes up into the flask with in-creasing speed, thereby forming a fountain and turns pink.
Ammonia gas is remarkably soluble in water according to
Because of the potential gradient the reaction takes place spontaneously.
Just a few drops of water are enough to decrease the pressure in the flask so drastically that water is drawn upward into it in a strong jet.
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