Manganese dioxide, reaction with potassium chlorate

It is used to make oxygen in laboratories. One has to heat a mixture of manganese dioxide and an alkaline chlorate. This reaction, which is known for not being dangerous and often used in lectures, gives rise to anhydrous manganese dichloride which reacts explosively with potassium or zinc. Detonation of the mixture is known to have led to several accidents. 

To make oxygen, potassium chlorate was heated with manganese dioxide. The manganese dioxide catalyzed the reaction and the potassium chlorate decomposed (broke down into its parts) ... 

Oxygen can be produced by electrolysis of water using a salt as an electrolyte that produces hydrogen at the opposite electrode. When potassium chlorate (KClOj) is heated in a test tube with a small amount of manganese dioxide (MnO ) as a catalyst, the chemical reaction that releases the oxygen from potassium chlorate will be accelerated. Use of potassium nitrate (KNOj) will also produce small amounts of oxygen. 

The second reaction is accelerated by catalyzers, such as manganese dioxide or ferric oxide, or in fact any material with a rough surface. Too high a temperature also causes reaction (2) principally to take place. On the other hand, if the temperature is maintained at the right point, the salt is free from dirt, and the inside of the crucible is perfectly clean and free from roughness, the decomposition proceeds mainly according to reaction (1). Potassium perchlorate is very sparingly soluble in cold water and may be separated from potassium chloride and any undecomposed potassium chlorate by crystallization. 

The reaction proceeds readily at a temperature just above the melting point of potassium chlorate if a small amount of manganese dioxide, Mn02, is mixed with it. Although the manganese dioxide accelerates the rate of evolution of oxygen from the potassium chlorate, it itself is not changed. 

Oxygen can be prepared by heating potassium chlorate, KCIO3, with manganese dioxide as a catalyst. The reaction is... 

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