Question

The swelling and shrinking nature of black cotton soil is primarily due to the presence of:

• A. Kaolinite
• B. Illite
• C. Montmorillonite
• D. Vermiculite

Hint:

For expansive soils, remember: - Montmorillonite: High swelling/shrinking. - Kaolinite: Low plasticity. - Illite: Moderate plasticity.

Answer 1

The Correct Option is C

Montmorillonite is a type of clay mineral with high swelling and shrinking properties. Black cotton soils contain a significant amount of montmorillonite, which is responsible for their expansive behavior. This property affects construction and agriculture on such soils.