Question

Write notes on the following:

Hint:

Galvanization provides long-lasting protection against corrosion, especially in environments where metals are exposed to moisture and air.

Answer 1

(a) Dissociation reaction:
A dissociation reaction refers to the process in which a compound breaks down into smaller components, typically ions or molecules. This occurs when the compound is dissolved in a solvent, such as water. For example, when sodium chloride (NaCl) is dissolved in water, it dissociates into sodium ions (Na\(^+\)) and chloride ions (Cl\(^-\)). Example: \[ \text{NaCl} \longrightarrow \text{Na}^+ + \text{Cl}^-. \]
(b) Corrosion:
Corrosion is the gradual degradation or deterioration of materials, especially metals, due to chemical reactions with the environment. One of the most common examples is the corrosion of iron, known as rusting, where iron reacts with oxygen and water to form iron oxide (Fe\(_2\)O\(_3\)). The reaction for rusting of iron is: \[ \text{Fe} + \text{O}_2 + \text{H}_2\text{O} \longrightarrow \text{Fe}_2\text{O}_3 \cdot x\text{H}_2\text{O} \quad (\text{rust}). \]
(c) Galvanization:
Galvanization is the process of coating iron or steel with a layer of zinc to prevent rusting or corrosion. The zinc layer acts as a protective barrier, and since zinc is more reactive than iron, it corrodes first, thus protecting the underlying metal. Galvanization is commonly used for outdoor structures, such as fences and roofs.
In the process, the metal is dipped into molten zinc, forming a protective coating. This process is widely used to protect metals from the damaging effects of corrosion.