Question

Which type of reaction is corrosion.

Answer 1

Hint : Oxidation reaction is a type of reaction in which the complex either accepts oxygen, or donate hydrogen or donates electrons. Reduction reaction is a type of reaction in which the complex either donates oxygen, or accepts hydrogen or accepts electrons. Oxidation and reduction collectively called redox reaction.

Complete Step By Step Answer:
The phenomena in which the metal surface is being ruined by the gases, water and other entities and leads to the formation of the compounds like oxides, carbonates, sulphides, sulphate, and other compounds is known as corrosion.
Corrosion is a redox type reaction. The corrosion occurring to the iron is termed as rust. Rust is simply the hydrated ferric oxide with formula $F{e_2}{O_3}.x{H_2}O$ . Corrosion in the case of silver is considered as tarnishing.
Factors promoting the corrosions are: - (i) reactivity of the metal, (ii) presence of impurities, (iii) presence of air and the moisture, (iv) strains in metals, (v) presence of electrolytes, and many more.
Prevention of corrosions are: - (i) Barrier protection like coating, painting, oiling, and others, (ii) sacrificial protection, (iii) electrical protection – cathodic protection, (iv) use of anti rust solution, and many more.

Note :
It is to remember, that corrosion to iron also called as rust will never occur if the pH is maintained above $9 - 10$ . Corrosions are of different types namely (i) uniform corrosion, (ii) pitting corrosion, (iii) crevice corrosion, (iv) intergranular corrosion, (v) stress corrosion cracking, (vi) galvanic corrosion, (vii) high temperature corrosion, (viii) microbial corrosion, and many more.