What is adsorption?

What is adsorption?

• A. A pesticide that dissolves easily in water
• B. A pesticide that evaporates quickly
• C. A pesticide that is rapidly degraded
• D. A pesticide held strongly to soil particles that is less likely to leach

Answer: (D)

Adsorption is the process of a substance sticking to surfaces rather than remaining dissolved in water. In soil, pesticide molecules attach to the surfaces of soil particles—especially clay minerals and organic matter—through interactions like electrostatic forces and van der Waals forces. When a pesticide is strongly adsorbed, it stays bound to the soil particles and is less likely to be carried away with percolating water, making leaching through the soil profile less probable. This is distinct from simply being dissolved, evaporating, or being degraded more quickly. So, describing a pesticide as held strongly to soil particles and less likely to leach captures the essence of adsorption: adherence to surfaces that reduces mobility in the soil.

Adsorption is the process of a substance sticking to surfaces rather than remaining dissolved in water. In soil, pesticide molecules attach to the surfaces of soil particles—especially clay minerals and organic matter—through interactions like electrostatic forces and van der Waals forces. When a pesticide is strongly adsorbed, it stays bound to the soil particles and is less likely to be carried away with percolating water, making leaching through the soil profile less probable. This is distinct from simply being dissolved, evaporating, or being degraded more quickly. So, describing a pesticide as held strongly to soil particles and less likely to leach captures the essence of adsorption: adherence to surfaces that reduces mobility in the soil.