Take 5 mL hydrogen peroxide solution in a test tube. Add a pinch of manganese dioxide to it. Show a burning match stick that is about to get extinguished into the test tube. What do you observe? Give reasons for your observation.

One can see that the dying flame gets “rejuvenated” or begins to burn properly (or one can say, the flame looks “live”).

Hydrogen peroxide (H₂O₂) by itself slowly decomposes into water and oxygen. When manganese dioxide (MnO₂) is added, the rate of decomposition is made faster, and O₂ is liberated at a faster rate. The oxygen supports the burning of match stick, and that is why one can see it burning effectively.

There is not any reaction involved, but the rate of decomposition of H₂O₂ is increased. Here, MnO₂ acts as a catalyst.