Question

Give the chemical formula of pyrolusite.

Answer 1

Hint : Pyrolusite is a mineral which mainly consists of manganese dioxide $Mn{O_2}$ . It is black in color. It appears in amorphous form. Out of all the manganese compounds found in nature, pyrolusite is considered as the most abundant compound. Manganese dioxide is used in batteries.

Complete Step By Step Answer:
Manganese dioxide when found naturally is called pyrolusite. It is insoluble in water. It is an odorless solid. It is widely used in industries like the ceramic industry. It is used in the manufacture of glass. As all the raw materials which are used in the glass industry contain some amount of iron which is in the form of ferric oxides, the use of manganese dioxide is highly useful. Pyrolusite ores are widely used in dry cell batteries. Many of these cells should be activated by chemical or physical means. Glass gets a tint because of impurities present in it. In this case manganese dioxide is used to get rid of green tint produced by iron impurities. It also acts as a catalyst in many chemical reactions. Preparation of oxygen in the laboratory requires manganese dioxide. It acts as an accelerant and when it is added to hydrogen peroxide, bubbles of oxygen are formed.
Therefore, the chemical formula of pyrolusite is $Mn{O_2}$ .

Note :
Pyrolusite is found on the ocean floor. The oxidation number of manganese in manganese dioxide is $+ 4$ . The brown-black pigments observed in paint are manganese dioxide. Manganese dioxide is used to make alloys which are used in soft drinks.