How to make a glowing fountain using luminol and hydrogen peroxide
Making a glowing fountain using luminol chemiluminescence
Wear protective gloves, eyewear, and a mask. Perform this experiment in a well-ventilated area.
Reagents and equipment
- 2 g sodium carbonate;
- 0.1 g luminol;
- 12 g sodium bicarbonate;
- 0.25 g ammonium carbonate;
- 0.2 copper(II) sulfate;
- 500 mL distilled water;
- 250 mL 3% hydrogen peroxide solution;
- 15 mL 25% ammonia solution;
- 3 g sodium hydroxide;
- one 500 mL beaker;
- two 250 mL beakers;
- one 2 L conical flask;
- one 100 mL conical flask;
- a stopper with 3 tubes;
- a magnetic induction stirrer and stirring bar;
- a stand;
- one syringe containing 25 mL water.
Place the 1 L beaker on the magnetic induction stirrer and place the stirring bar inside. Add, in order: 500 mL distilled water, 2 g sodium carbonate, 0.1 g luminol, 12 g sodium bicarbonate, 0.25 g ammonium carbonate, 0.2 g copper(II) sulfate. Stir until fully dissolved to obtain the luminol solution. The solution should turn green. Fix the 2 L conical flask upside down in the stand and fill with gaseous ammonia. To do this, pour 15 mL 25% ammonia solution into the 100 mL conical flask. Add 3 g sodium hydroxide. Insert the neck of the small flask into the neck of the large flask until you can smell the sharp odor of ammonia. Immediately close the large flask using the stopper with three tubes. Fill one 250 mL beaker with 3% hydrogen peroxide solution, and the other with the luminol solution you prepared. Put two of the stopper tubes in these beakers – and keep in mind that these tubes are connected by an adapter. Connect the third tube to the syringe containing 25 mL of water. Inject the water, turn out the lights, and watch the luminous fountain in the flask!
The release of light as the result of a chemical reaction is known as chemiluminescence. Luminol has the ability to release light when oxidized by an oxidizing agent such as hydrogen peroxide. Copper(II) ions allow for hydrogen peroxide to dissociate into oxygen and water; they also catalyze the oxidation of luminol by this oxygen in a basic medium. Luminol turns into an unstable particle, which releases light as it returns to a stable form.
С₈H₇N₃O₂ + 2OH⁻ ⇄ C₈H₅N₃O₂²⁻ + 2H₂O
2H₂O₂ + Cu²⁺(catalyst) = O₂ + 2H₂O
C₈H₅N₃O₂²⁻ + O₂ + Cu²⁺(catalyst)= С₈H₇NO₄²⁻ + N₂ + blue light
When sodium hydroxide dissolves, it releases heat, which lowers ammonia’s solubility in water. Since ammonia is lighter than air, it fills the flask and forces the air already in the flask out.
The ammonia in the flask then begins to dissolve in the water that we “inject” using the syringe. The pressure level in the flask lowers, and the solutions in the beakers are drawn into the flask. Their components mingle, react, and create the glowing fountain you see.