Question

How will you demonstrate the solubility of ammonia in water? Explain.

Answer 1

The set up used to demonstrate the solubility of ammonia in water is shown in the following figure.


A round-bottom flask containing ammonia is fitted with a two-holed cork and mounted. A dropper containing water is placed in one of the holes and a jet tube is placed in the other hole. The bottom of the jet tube is immersed in a beaker containing red litmus solution.
The bulb of the dropper is pressed to allow some water to drop in the beaker. It is observed that the red litmus solution enters in the round-bottom flask through the jet tube and forms a fountain in the flask. The jet strikes the walls of the flask and turns blue.
When water is introduced in the flask containing ammonia, ammonia dissolves in the water completely and causes a reduction in pressure in the round bottomed flask. Atmospheric pressure then forces the red litmus solution to rise into the flask, where it reacts with the alkaline ammonia solution in the flask and turns blue. This shows that ammonia is highly soluble in water.