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.
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