The process whereby certain minerals absorb water, expand and change is called as

Hydration is a chemical weathering process involving the absorption of water into the crystal structure of minerals [1]. This process involves the rigid attachment of H+ and OH- ions to the atoms and molecules of a mineral, leading to a significant increase in volume [1]. For instance, the mineral anhydrite absorbs water to transform into gypsum, which is larger in volume [2]. This expansion creates physical stresses within the rock, leading to fatigue, disintegration, and phenomena like exfoliation or granular disintegration [1]. While hydrolysis involves water reacting to break chemical bonds and form new solutions, and oxidation involves reactions with oxygen, hydration specifically refers to the absorption and subsequent swelling of minerals [2]. This repeated expansion and contraction weakens the rock's overall structure over time [1].

Sources

1. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 6: Geomorphic Movements > Hydration > p. 91
2. [2] https://education.nationalgeographic.org/resource/weathering/