Coal is a fossil fuel. It contains carbon, hydrogen and oxygen. It also contains nitrogen, phosphorus and sulphur. It occurs in the solid state. It is of four types.
- Peat: Formation of peat is the first step in the formation of coal. It contains a high proportion of water and less than 60% of carbon.
Therefore, not much heat can be obtained from peat.
- Lignite: Peat was transformed into Lignite due to increased pressure and temperature inside the earth. It contains 60 to 70% of carbon.- Lignite is the second step of the formation of coal.
- Bituminous coal: Bituminous coal was formed as the third step of formation of coal. It contains 70 to 90% of carbon. Anthracite:
- Anthracite is known as the pure form of coal. This coal is hard and contains about 95% of carbon.
Uses of coal:
- Coal is used as fuel in factories and homes.
- Coal is used to obtain coke, coal gas and coal tar.
- Coal is used in thermal power plants for generation of electricity.
