Catalytic Decomposition of H2O2 – Elephant’s Toothpaste Experiment
Elephant's toothpaste is a foamy substance formed as a result of rapid decomposition of hydrogen peroxide. Elephant’s toothpaste reaction experiment is generally used for classroom demonstrations as it requires fewer ingredients and makes a "volcano of foam".
H2O2 is decomposed by Iodide Ion. Iodide ion is used as a catalyst and these iodide ions come from KI (Potassium Iodide) or NaI (Sodium Iodide). This decomposition reaction liberates water, oxygen and heat.
30% H2O2 (Hydrogen Peroxide)
1 Liter Graduated cylinder
KI (Potassium Iodide) or NaI (Sodium Iodide).
Food Color for fun
Liquid Dish Detergent
1. Pour 50 mL of 30% H2O2 (Hydrogen Peroxide) in 1 L graduated cylinder.
2. Then, add 3-4 drops of food color in 1 L graduated cylinder to make colored H2O2 solution.
3. Then, start adding liquid dish detergent or soap from the side of 1 L graduated cylinder to make a small layer of liquid dish detergent or soap over colored H2O2 solution.
4. With the help of small beaker add KI or NaI in the cylinder containing H2O2 solution. As a result of reaction, oxygen gas generated and this gas creates large amount of colored foam. This foam comes out of graduated cylinder.
Decomposition of H2O2 (Hydrogen Peroxide) yields O2 (oxygen) and H2O (water). Reaction is catalyzed by I- (Iodide Ion); These Iodide Ion comes from KI or NaI
H2O2 (Aq) + I-1 (Aq) ---> H2O (liquid) + IO- (Aq)
IO- (Aq) + H2O2 (Aq) ---> H2O (liquid) +O2 (g) + I- (Aq)
2H2O2 (Aq) ---> 2H2O (liquid) +O2 (g)