Question

Action of heat on potassium permanganate at \[746K\] results in the formation of

Answer 1

Hint: At such a higher temperature the potassium permanganate decomposes. There are three products formed when decomposition occurs. One of which is an oxygen gas, which liberates out. The other two products are manganese products, with an oxidation state of manganese \[ + 6\] and \[ + 4\].

Complete answer:
 When potassium permanganate is subjected to a higher temperature of \[746K\], it results in its thermal decomposition. On decomposition, it produces potassium manganate and manganese dioxide with the liberation of oxygen gas. The reaction takes place in the following manner:
\[2KMn{O_4} \to {K_2}Mn{O_4} + Mn{O_4} + {O_2}\]
During this reaction, the potassium permanganate is in solid form. And the products obtained are also solid except oxygen.
Potassium permanganate is an inorganic, purplish-black crystalline salt. It dissolves in water to give pink or purple solutions. It is manufactured in industries from manganese dioxide which also occurs as mineral pyrolusite. It is a very strong oxidizing agent and hence used in the laboratory in a variety of experiments of titration. A dilute solution of potassium permanganate is used to test the presence of unsaturation. Its major application is in the synthesis of organic compounds such as ascorbic acid, chloramphenicol, saccharin, etc. Potassium permanganate is added to "plastic sphere dispensers" to create backfires, burnouts, and controlled burns. The permanganate delays the ripening of fruits, increasing the fruit's shelf life up to \[4\] weeks without the need for refrigeration. Potassium permanganate is one of the principal chemicals used in the film and television industries to "age" props and set dressings, as its conversion to brown MnO2 creates "hundred-year-old" or "ancient" looks.

Note:
In thermal decomposition reaction, the oxidation state of potassium permanganate is \[ + 7\] . After decomposition the potassium manganate is formed which has oxidation number \[ + 6\] and manganese dioxide has \[ + 4\]. Potassium permanganate is a strong oxidizer and it should be handled carefully as its exposure to skin can result in a long-lasting brown stain.