Elephant Toothpaste

What reaction is taking place here.

We have hydrogen peroxide in a graduated cylinder and we add potassium iodide (KI). The result is we see a mess load of bubbles as well as excess heat. Those bubbles are oxygen gas.

Here is the equation.

2H₂O₂ -> 2H₂O + O₂

Notice anything? The Potassium Iodide is not in the reaction directly, but it serves as a catalyst in the reaction. A catalyst does not get consumed in the reaction but speeds up the rate of reaction. It is the key to the Elephant Toothpaste experiment. The above equation showing the breakdown of hydrogen peroxide into water and oxygen gas is exothermic, meaning that it gives off heat. If we did not add the catalyst the breakdown would still occur at a much much slower rate. You would have to leave out the hydrogen peroxide for quite a long time to see it breakdown into water and oxygen without a catalyst, but it would occur. The catalyst speeds up the process to where we see the violent explosion in the video. Other compounds can be used as catalysts as well. Metals are often good catalysts, and we can use not only potassium (from Potassium Iodide or Potassium Sulfate), but Magnesium (from Magnesium Dioxide) as seen in the video below.

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