Question

What are the main types of chemical weathering?

Answer 1

Water plays an important role in chemical weathering. Rock is a mixture of many minerals. Water is a universal solvent. Many things get dissolved easily in water. The solubility increases because the matter has dissolved in water. And those materials which do not dissolve easily in water get dissolved in such solutions. In areas that receive heavy rainfall, chemical weathering occurs in the following way.

1. Carbonation: The rainwater travels through the atmosphere before reaching the ground. Carbon dioxide in the air gets mixed in the water in this process. Dilute carbonic acid gets formed. Materials like limestone get easily dissolved in such acids.
2. Solution: Some minerals in the rock get dissolved in water. Limestone is formed due to chemical precipitation between water and alkalis. Similarly, because of solution, alkalis in the rock dissolve and make them brittle.
3. Oxidation: This process occurs in rocks which have iron present in them. The iron in the rock comes in contact with water and chemical reaction takes place between iron and oxygen. Hence, a reddish coloured layer forms on the rocks.