Question

Explain corrosion by giving example.

Hint:

Corrosion is most common in metals like iron; preventive coatings like paint or galvanization can significantly reduce it.

Answer 1

Step 1: Definition.
Corrosion is a slow process in which metals are eaten away by the action of air, water, or chemicals present in the surroundings. It results in the formation of undesirable compounds like metal oxides or carbonates.
Step 2: Example — Rusting of Iron.
When iron is exposed to moist air, it reacts with oxygen and water to form a reddish-brown flaky layer of hydrated ferric oxide (rust). \[ 4\text{Fe} + 3\text{O}_2 + 6\text{H}_2\text{O} \rightarrow 4\text{Fe(OH)}_3 \] On drying, it forms Fe2O3·xH2O (rust).
Step 3: Prevention methods.
Corrosion can be prevented by painting, galvanizing, oiling, greasing, or electroplating the metal surface.
Step 4: Conclusion.
Thus, corrosion weakens metals and causes damage to structures like bridges, ships, and iron railings.