Which one of the following is not a type of chemical weathering?

Chemical Weathering
- Chemical weathering in geology is the process by which rocks are slowly broken down through chemical reactions, often resulting in a different substance entirely.
- A cluster of weathering processes namely solution, carbonation, hydration, oxidation, and reduction. Hence Option 2 is correct.
- These processes act on rocks to decompose, dissolve or moderate them to a fine clastic state through chemical reactions by oxygen, surface/ soil water, and other acids.
- Water and air along with heat must be present to speed up all chemical reactions.
Solution
- When substances are dissolved in acids or water, then the water or acid with dissolved substances is called a solution.
- This process includes the removal of solids in solution and depends upon the solubility of a mineral in weak acids or water.
Carbonation
- Carbonation is the reaction of bicarbonate and carbonate with minerals.
- It is a general process helping the fragmentation of feldspars and carbonate minerals.
- Carbon dioxide from the soil and atmospheric air is absorbed by water to form carbonic acid that acts like weak acid.
Hydration
- Hydration is the chemical addition of water.
  Minerals take up water and enlarge.
- This enlargement causes an increase in the volume of the material itself or rock.
Oxidation and Reduction
- In weathering, oxidation denotes a mixture of a mineral with oxygen to form hydroxides or oxides.
  Oxidation happens where there is ready access to the oxygenated waters and atmosphere.
- The minerals commonly involved in this process are manganese, sulphur, iron, etc.
- When oxidised minerals are positioned in a situation where oxygen is absent, the reduction occurs.
- Such circumstances exist commonly below the water table, on waterlogged ground and in areas of stagnant water.
- These weathering processes are interconnected.