Question

What are the main types of chemical weathering?

Answer 1

The process of decomposition of rocks due to changes in their chemical composition is called chemical weathering.
Its main types are:
(i) Carbonation

• When the rain water mixes with the carbon dioxide in the atmosphere it leads to the formation of dilute carbonic acid.
• Many rocks like limestone get easily dissolved in such acids.

(ii) Solution

• Some minerals in the rock get dissolved in water.
• Because of this solution, alkalis in the rock dissolve and make them brittle.

(iii) Oxidation

• This process occurs in rocks which have iron present in them. The iron in the rock comes in contact with water and a chemical reaction takes place between iron and oxygen.
• Hence, a reddish coloured layer forms on the rocks. This is called rust.
• It occurs in rocks in areas with high rainfall.