potassium permanganate

Question

potassium permanganate decompose under light變乜?

答非所問!!!!
I will ignore such answer

Answer 1

In the presence of light, KMnO4(aq) solution decomposes to give MnO2(s) and O2(g).
2KMnO4(aq) → K2MnO4(aq) + 2MnO2(aq) + O2

Answer 2

Potassium permanganate is the chemical compound KMnO4. In this salt, manganese is in the +7 oxidation state. The salt is also known as "permanganate of potash" and "Condy's crystals". The permanganate ion is a strong oxidizing agent. It dissolves in water to give deep purple solutions, evaporation of which gives prismatic purple-black glistening crystals.[1] It has a sweet taste and is odourless. [2]

Sodium permanganate has essentially the same properties and use as potassium permanganate and can be used as its direct substitute.

simply heating can increase the reaction rate and the yield.

to compare, potassium permanganate is a stronger oxidizing agent than potassium dichromate (both are in aicdic medium). however, potassium permanganate is just too strong for oxidation of organic molecules. it may further oxidize the product formed (ie, ethanoic acid) into carbon dioxide and water, though it is not very common.

instead, milder oxidizing agents, such as potassium dichromate, are used. with similar reactions and reactivity, it will not produce carbon dioxide and water in oxidation reactions.