Answer:
method used is decomposition
Step-by-step explanation:
Hydrogen Peroxide (H2O2) will decompose rapidly in the presence of Manganese Dioxide, acting as the catalyst, to produce Oxygen gas and water.
When the Hydrogen Peroxide and Manganese Dioxide are mixed, Oxygen gas bubbles should be seen coming from the mixture. One can collect this Oxygen gas produced over water (through water-displacement) and store it inside a bottle for later use.