Question

Chemical weathering involving complete disintegration or modification in structure and composition of primary minerals is –

• A. Hydration
• B. Oxidation
• C. Hydrolysis
• D. Carbonation

Hint:

Hydrolysis alters minerals most thoroughly—especially silicates like feldspar into clay.

Answer 1

The Correct Option is C

Hydrolysis is the most significant chemical weathering process, where hydrogen ions replace metal ions in minerals, leading to complete structural and compositional changes.

Answer 2

Elimination approach:
Hydration only involves water molecules attaching to a mineral's surface or lattice without breaking its structure, a reversible and relatively minor change. Oxidation affects only elements capable of changing valence, chiefly iron and manganese compounds. Carbonation is restricted to minerals containing carbonate-reactive cations. In contrast, hydrolysis attacks the very silicate structure of primary minerals, \( \text{H}^+ \) ions from water replace basic cations (\( \text{K}^+, \text{Na}^+, \text{Ca}^{2+} \)) within the crystal lattice, breaking Si-O-Al bonds and completely transforming the mineral into new secondary clay minerals. This wholesale structural and compositional change is why hydrolysis, not the other processes, causes complete disintegration of primary minerals.