Question

What is Corrosion? Explain its Advantage and Disadvantage?

Answer 1

Part 1: Definition

1. Corrosion is a process of deterioration of metals as a result of its reaction with air or water due to some chemical reaction on its surface.
2. The phenomenon of corrosion can be explained with the help of the electrochemical theory of corrosion which involves oxidation and reduction reactions.
3. Corrosion is a spontaneous process and is mainly caused due to oxidation of metals. For example- Rusting of Iron.
4. The chemical reaction related to corrosion is as follows:
   $4\mathrm{Fe}\left(\mathrm{s}\right)+3{\mathrm{O}}_2\left(\mathrm{g}\right)+{\mathrm{xH}}_2\mathrm{O}\left(\mathrm{l}\right)\to \underset{\left(\mathrm{Rust}\right)}{2{\mathrm{Fe}}_2{\mathrm{O}}_3.{\mathrm{xH}}_2\mathrm{O}\left(\mathrm{s}\right)}$

Part 2: Disadvantage of Corrosion

1. Corrosion weakens the Iron objects and structures such as car bodies, bridges, railings, ships, etc.
2. A lot of money has to be spent annually to prevent the corrosion of iron and steel objects and to replace the damaged structures.

Part 3: Advantages of Corrosion

1. Corrosion prevents corrosion because oxide layers of some metals protect the inner lining of iron metal to prevent it to come in direct contact with air.
2. The galvanic corrosion method is very useful when two electrodes come in contact via an electrolyte and an electric field is applied. Thus, it prevents the corrosion of actual metal in the reaction.