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Decomposition of H₂O₂ with MnO₂


Avoid contact with hydrogen peroxide.

Chemicals and Solutions

  • Hydrogen Peroxide, 30%
  • Manganese Dioxide, solid


  • cylinder
  • spatula


Pour some hydrogen peroxide into the cylinder and add a small spatula scoop of MnO₂. Bubbles of O₂ will form immediately (the reaction also produces heat).

Alternate Procedure: Genie in a bottle

Apparatus and Materials

  • vase or foil covered bottle with stopper
  • tea bag
  • solid MnO
  • 30 mL of 30 % hydrogen peroxide


  1. Use a vase or cover a pop bottle with foil so students cannot see inside the bottle.
  2. Place 30 mL of 30% hydrogen peroxide (USE CARE!) in the bottle.
  3. Carefully remove the tea from a tea bag and in its place put in solid manganese dioxide.
  4. Now put the "tea bag" in the bottle such that it dangles above the hydrogen peroxide. Stabilize the "tea bag" in this position by inserting a stopper.
  5. When you are ready to present the demonstration simply remove the stopper and release the "genie".
  6. The "tea bag" of MnO₂ will fall into the hydrogen peroxide catalyzing the following reaction:


\( \ce{ H2O2 -> H2O + O2 } \)