The correct answer is Corrosion.

• There are different types of chemical weathering processes such as solution, hydration, carbonation, oxidation, reduction, and biological.
• Hence corrosion is not a type of chemical weathering.

• Chemical Weathering
  • It is a cluster of weathering processes namely as a solution, hydration, carbonation, oxidation, reduction, and biological.
  • 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 weathering
  • Solution weathering occurs when the solvent is an acidic solution rather than simple water.
• 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.
  • This process is long and reversible.
  • This may lead to their disintegration of rocks.
• Carbonation,
  • Carbonation is the reaction of bicarbonate and carbonate with minerals.
  • It is a general process that helps 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.
  • These acids act on various surfaces and erode them.
• Oxidation and Reduction,
  • In weathering, oxidation denotes the forming of a mixture of a mineral with oxygen to form hydroxides or oxides.
  • Oxidation happens where there is ready access to the oxygenated water.
  • The minerals commonly involved in this process are manganese, sulfur, iron, etc.
  • In the process of oxidation, rock fragmentation happens due to the disturbance caused by the addition of oxygen.
  • Oxidation and reduction processes are interconnected.​
• Biological activity and weathering
  • Decaying plant and animal matter help in the production of humic, carbonic, and other acids which enhance decay and solubility of some elements.