Which one among the following processes is not part of a chemical weathering ?

Weathering is categorized into physical (mechanical), chemical, and biological processes [2]. Chemical weathering involves the decomposition of rocks through chemical reactions that alter their mineralogy. Key chemical processes include solution (dissolution), where minerals dissolve in water [1]; hydration, where minerals absorb water and expand [2]; and oxidation, where minerals react with oxygen [2]. In contrast, exfoliation is a physical weathering process. It involves the flaking off of rock layers due to expansion and contraction caused by temperature changes or unloading [1]. While exfoliation is often described as a result of physical stresses, it is explicitly classified as a mechanical process rather than a chemical one. Therefore, exfoliation is the only option listed that is not a part of chemical weathering.

Sources

1. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 6: Geomorphic Movements > Weathering > p. 83
2. [1] FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 5: Geomorphic Processes > Exfoliation > p. 41