Question

(i) Explain Corrosion. Write its two examples.

Hint:

Corrosion can be prevented using protective coatings, like painting, galvanization, or using corrosion-resistant materials.

Answer 1

Corrosion is the gradual destruction or deterioration of materials, typically metals, due to chemical reactions with their environment, often with water and oxygen. The most common example of corrosion is rusting of iron. Corrosion occurs when metals react with environmental elements, leading to the formation of metal oxides and other compounds that weaken the structure of the material. Examples of Corrosion:
1. Rusting of Iron:
The corrosion of iron is called rusting. When iron reacts with oxygen and water, it forms iron oxide (rust). The reaction is: \[ 4Fe + 3O_2 + 6H_2O \rightarrow 4Fe(OH)_3 \] This reaction leads to the degradation of the iron structure, making it weaker and more brittle. 2. Tarnishing of Silver:
Silver tarnishes when it reacts with sulfur compounds in the air, forming silver sulfide. The tarnish appears as a dark discoloration on silver objects. \[ 2Ag + H_2S \rightarrow Ag_2S + H_2 \]