Question

What do you mean by corrosion? Name the factors that affect corrosion. [3 MARKS]

Answer 1

Definition: 1 Mark
Factors: 0.5 Mark each


Corrosion is a natural process, which converts a refined metal to a more chemically-stable form, such as its oxide, hydroxide, or sulfide. It is the gradual destruction of materials (usually metals) by chemical and/or electrochemical reaction with their environment.

The factors which affect corrosion are:

1. More the reactivity of the metal, more will be the possibility of the metal getting corroded.

2. Presence of carbon dioxide in natural water increases rusting of iron.

3. When the iron surface is coated with layers of metals more active than iron, then the rate of corrosion is retarded.

4. A rise in temperature (within a reasonable limit) increases the rate of corrosion.