Ammonia Fountain

Ammonia is generated in a plastic pipete and collected in a small test tube which is later closed with rubber stoper with needle and immersed in water.

Materials
Test tube with rubber stopper and hypodermic needle, stand  that fits to the pipette, plastic pipette, 2.5 mL syringe, hypodermic needle (0.8 mm/40 mm), isolation tape, cutting pliers, a pair of scissors or scalpel and tweezers.

Chemicals
4 small grains of NaOH (rise grain size), 2 mL saturated NH₄Cl solution, phenolphthalein solution

Safety tips
Wear safety goggles! Syringe needle’s tip is sharp! You must be careful while piercing the pipette’s bulb.
Always use syringe needles with wide diameter (0.8 mm -1.2 mm) in order to avoid case of clogging when there is possible reaction of reagent with the needle metal.

Fig. 1. Generation of ammonia

Fig. 2. Setup for the fountain

Experimental

• The apparatus should be assembled as it shown on Fig. 1.
• Prepare solution of few drops of phenolphthalein in 20 mL water in a vial;
• Make ammonia and collect it in the test tube;
• When the test tube is filled with ammonia close it with the rubber stopper with a needle and deep it into the water with phenolphthalein Fig. 2. The rubber stopper should be below the water surface.
• Observe the setup for few minutes and do not take the test tube out of water.
• Do not throw the pipette gas generator, it can be reused.
• Return the materials and chemicals to its place.