This reaction demonstrates the exothermic nature of the decomposition of hydrogen peroxide into oxygen and water.

Place 10 ml of 30% Hydrogen Peroxide solution in a 250 ml conical flask. Place the flask in a in a container with water, as shown on the right. Using a small spatula place a small amount of manganese dioxide int he flask.

This demonstration must be conducted under a fumehood or outdoors. Eye protection must be worn.

A thick cloud of smoke (water vapour) appears quickly after the addition of manganese dioxide powder(MnO₂ ). The manganese dioxide acts as a catalyst speeding up the rate of the reaction shown below.

2H₂O_2(l) => O_2(g) + 2H₂O_(g)

Notice the amount of heat given off from the reaction.

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