Question

What property of Ammonia is demonstrated by the fountain experiment?

Answer 1

The fountain experiment is an experiment used to show the high solubility of polar gas. In the ammonia fountain experiment, the ammonia gas is filled inside the whole flask and a few amounts of water is injected inside the round bottom flask from the trough of water.

Complete answer:
As we know that the water dissolves the ammonia gas which lowers the pressure inside the flask and more water gets sucked inside the flask from the trough of water, creating a scenario similar to a fountain. The flask with ammonium hydroxide solution. We use a glass rod that is dipped in ammonium hydroxide solution and introduces the glass rod near the flask. If it forms white dense fumes, then the gas present in the flask is $HCl$. The $HCl$ reacts with ammonium hydroxide and gives ammonium chloride and water.
A round bottomed flask is filled with a hydrogen chloride in gaseous form. The flask is sealed with a rubber bung through which a glass tube is inserted, drawn to jet on the inside of the flask. The flask is inverted so the glass tube is placed in a beaker of water, the water rising up the tube making a fountain inside the flask. During the procedure of the Fountain experiment, as the dropper containing water is squeezed or injected in the flask, a colored fountain is obtained which testifies the name of the experiment. This shows that gas present in the flask dissolves in water due to its high solubility
$N{{H}_{4}}OH+HCl\to N{{H}_{4}}Cl+{{H}_{2}}O$
The white dense fumes observed are due to the formation of ammonium chloride and by the fountain experiment, we demonstrate the high solubility of ammonia gas in water.

Note:
Remember that the Fountain Experiment is basically a classic demonstration in which a large round bottomed flask containing a soluble gas such as ammonia is clamped upside down and connected to a trough of water containing an indicator by a glass tube.