Catalytic Decomposition of Hydrogen Peroxide H2O2 – Elephant’s Toothpaste Experiment

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".

Description:

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.

Materials:

30% H₂O₂ (Hydrogen Peroxide)

1 Liter Graduated cylinder

KI (Potassium Iodide) or NaI (Sodium Iodide).

Food Color for fun

Liquid Dish Detergent

Procedure:

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.

Discussion:

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

Reaction-

H₂O₂ (Aq) + I^-1 (Aq) ---> H₂O (liquid) + IO^- (Aq)

IO^- (Aq) + H₂O₂ (Aq) ---> H₂O (liquid) +O₂ (g) + I^- (Aq)

Overall Reaction-

2H₂O₂ (Aq) ---> 2H₂O (liquid) +O₂ (g)

Safety:

Wear proper protective equipment likes hand-gloves and safety goggles when preparing and demonstrating this experiment. Remember concentrated H₂O₂ (Hydrogen Peroxide) can cause burns.

Video of Catalytic Decomposition of H₂O₂ – Elephant’s Toothpaste Experiment: