Question

Define corrosion. corrosion is a process of reverse extractive metallurgy: explain with an example of extraction of iron

Answer 1

When a metal is attacked by substances around it such as moisture, acids, etc. it is said to corrode and this process is called corrosion.
when iron is in contact with moisture and air its layer gets corroded

Answer 2

Corrosion is a natural process of destruction like earthquakes, floods, volcanic eruptions, etc. Corrosion is the surface wastage that occurs when metals are exposed to reactive environments. Corrosion is the result of interaction between a metal and environments which results in its gradual destruction.

During extraction of metallurgy, the metals are extracted from their ores by reduction process in pure metallic state / form .

Metals are unstable and considered to be in the excited state.

Therefore, the extracted metals have a tendency to go back to combined form of an ore .

Hence, corrosion is considered smelting in reverse , or it is considered as reverse of metal extraction.

Iron is extracted in the form of:

Haematite, $Fe_{2}O_{3}$ .

Limonite,  $2Fe_{2}O_{3}$.$3H_{2}O$

Magnetite, $Fe_{3} O_{4}$

Iron pyrite, $FeS_{2}$

Corrosion is extractive metallurgy in reverse. For instance, iron is made from hematite by heating. Iron corrodes and reverts to rust after completing its life cycle. The hematite and rust have the same composition