Ammonia Fountain
A rubber bulb containing a small quantity of water is attached to an inverted flask full of ammonia gas. A long tube extends from within the inverted flask of ammonia into a large container full of phenolphthalein and water. When the water is squeezed from the rubber bulb into the flask, the ammonia gas dissolves, causing reduced pressure that allows atmospheric pressure to force water from the reservoir into the flask. In the basic ammonia solution, the phenolphthalein turns pink. A diagram of the system follows.
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Keywords
solubility of ammonia, solubility, descriptive chemistry - ammonia, pH, indicators, acids and bases, solutions, gases, ammonia solubility, solution of a gas in a liquid
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A rubber bulb is filled with water and placed onto a glass tube that extends into a flask of ammonia gas. Ammonia gas is extremely soluble in water. When the bulb is squeezed, the flask fills with liquid that turns pink, indicating a basic solution of ammonia. As the ammonia dissolved, the internal pressure was reduced, and atmospheric pressure forced water up from the bottom container.
Diagram of the apparatus 
Discussion
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Demonstration Notes: Warnings, Safety Information, etc.
Exam and Quiz Questions
1. What happened to the ammonia gas that was in the flask?
2. Based upon the color of the phenolpthalein indicator, is the solution in the flask acidic or basic?
3. What caused liquid to flow from the reservoir into the flask?