What are decomposition reactions?

A decomposition reaction is a type of chemical reaction in which a single compound breaks down into two or more simpler substances.

It is generally represented as:
AB → A + B

This breakdown can occur due to different forms of energy such as heat, light, or electricity.

Based on the energy source, decomposition reactions are classified into:

• Thermal decomposition
  Breakdown caused by heat
  Example: Calcium carbonate → Calcium oxide + Carbon dioxide
• Electrolytic decomposition
  Breakdown using electric current
  Example: Water → Hydrogen + Oxygen
• Photodecomposition
  Breakdown due to light energy
  Example: Silver chloride → Silver + Chlorine (in sunlight)

Concept clarity:
Unlike combination reactions, where substances join together, decomposition reactions involve splitting a compound into simpler parts.

Real relevance:
These reactions are widely used in industries, laboratory processes, and even in natural chemical cycles.