Decomposition and disintegration and decomposition of rocks due to chemical reaction is called chemical weathering. Chemical weathering takes place through the process of solution, oxidation and carbonation. Solution refers to the dissolution of soluble particles and minerals from the rocks with the help of water in motion. The atmospheric oxygen in rain water when meet with mineral like iron, rusting takes place and the colour of the rock changes. The process is called oxidation. When the carbon dioxide present in water reacts with rocks new chemical substances like calcium carbonation and iron carbonate are formed. This process is called carbonation.