Drop a chemical into a flask to produce a cloud of water vapor and oxygen, resembling a magic genie emerging from its bottle. This chemistry demonstration can be used to introduce the concepts of decomposition reactions, exothermic reactions, and catalysts.
Magic Genie Safety
Wear rubber gloves and safety goggles. The 30% hydrogen peroxide used in this demonstration is a strong oxidizing agent which should be handled with care. It is extremely corrosive and reactive. Sodium iodide should not be ingested. The chemical reaction evolves heat so it is important to use borosilicate glass and to take care that the mouth of the flask is directed away from people.
Magic Genie Demonstration Materials
- 50 ml of 30% hydrogen peroxide (H2O2)
- 4 g of sodium iodide, NaI may substitute manganese(IV) oxide
- 1-liter borosilicate (Pyrex or Kimax) volumetric flask
- Filter paper or tissue paper
The peroxide solution is considerably more concentrated than ordinary household peroxide (3%), so you'll either need to obtain it from a beauty supply store, chemical supply store or online. Sodium iodide or manganese oxide are best obtained from chemical suppliers.
Magic Genie Procedure
- Wrap the sodium iodide or manganese oxide in a piece of filter paper or tissue paper. Staple the paper so none of the solid can spill out.
- Carefully pour 50 ml of 30% hydrogen peroxide solution into the volumetric flask.
- Set the flask a counter and cover it with a towel to protect your hands from the heat of the reaction. When you are ready, drop the packet of solid reactant into the flask. Be sure the flask is pointed away from yourself and students. The magic water vapor genie will appear!
- After the demonstration is complete, the liquid may be washed down the drain with excess water. Rinse the flask and dilute any spills with water before cleanup.
Magic Genie Reaction
Hydrogen peroxide decomposes into water vapor and oxygen gas. The sodium iodide or manganese oxide catalyzes the exothermic reaction. The reaction is:
2H2O2 (aq) → 2H2O (g) + O2 (g) + heat
Helpful Tips for the Magic Genie Experiment
- Use of Pyrex, Kimax, or another type of borosilicate glass minimizes the risk of breakage.
- Rather than dropping the packet of sodium iodide or manganese oxide, you can hang it inside the flask by a string taped to the outside of the flask or secured (loosely) with a stopper. Do not tightly seal the flask! A stopper with a hole or two is safest.
- Use a large volume flask, even though you're only using a small volume of liquid. This is because brown liquid can splash up near the conclusion of the reaction. This liquid is free iodine released from the oxidizing effect of the strong peroxide solution.
- Make sure you don't seal or tightly stopper the flask, as pressure buildup from a premature reaction can shatter the flask violently.
- Excess sodium iodide may be thrown away in the trash receptacle.
- Are you artistic? You can wrap the flask in foil to make it look like a magic genie bottle or lamp.
While you have the 30% peroxide out, why not try the elephant toothpaste demonstration? Another interesting demonstration to try involves making violet smoke.
Reference: Stone, Charles, H. J. Chem. Ed., 1944, 21, 300.