Chemical weathering: Decomposition and disintegration of rocks due to chemical reaction is called chemical weathering. the gaseous component of the atmosphere like oxygen, carbon-di-oxide, water vapour react with the minerals of rocks and changes from old minerals to new minerals. Both physical and chemical properties has been changed within the rocks. This process is termed as chemical weathering. the rate chemical weathering is varies from place to place. Chemical weathering is mostly pronounced in hot and humid region. High temperature and huge availability of water is responsible for chemical weathering. but, it is least effective in cold and hot region.
Chemical weathering is of five types.
Oxidation: it is a simple process when atmospheric oxygen mixed with water and reacted the rocks having several types of oxides, iron oxide that weakens the rocks to disintegrate. Here oxygen mixed water react with ferrous oxide and turns into ferric oxide. Thus, iron bearing rocks produces rust and this rust weakens the rocks to disintegrate.
Carbonation: the atmospheric carbon di oxide when mixed with rain water it produces carbonic acid. This carbonic acid react with limestone and produces calcium bi carbonate. Calcium bi carbonate is easily dissolved in water. Karst region is the best example where this chemical weathering is very prominent.
Solution: it refers to the rocks having soluble minerals and dissolved with rain water, distilled water, acidic water, is called as solution.
Hydrolysis: here the hydrogen and hydroxyl ions of water react with the rocks composed of mica and feldper which weakens and disintegrate the rocks.
Hydration: when water react with the rocks composed of mica and feldspar, the mineral particles increases its volume which weakens and disintegrated the rocks. This process is called hydration.