“Chemical genie” experiment
How to make a genie from magnesium powder and crystal iodine
Do you think miracles only happen in fairy tales? In this experiment you’ll see how to summon a genie in a chemical laboratory!
Wear protective gloves and glasses and work in a well-ventilated room.
Warning! Do not try this at home. Only under professional supervision.
Reagents and equipment:
- magnesium powder;
- crystal iodine;
- test tube;
Into the test tube, we sprinkle magnesium powder and crystalline iodine in the ratio of 3:2. We add a few drops of water.
Magnesium is covered with an oxide film which protects it from chemical impact, so it does not react without iodine without outside help. If a little water is added, a reaction begins with the formation of magnesium iodide. Gaseous iodine will be released in the form of a thick violet vapor, as the reaction is accompanied by a large release of heat.
Iodine dissolves very poorly in water, but even this low solubility is sufficient for the reaction:
I₂ + H₂O → HIO +HI
The hydroiodic acid that forms dissolves the oxide film on the surface of the magnesium and reacts with the “bared” metal.
MgO + 2HI → MgI₂ + H₂O