Question

Small particles of sand in river water are removed by the process of

• A. decantation
• B. evaporation
• C. filtration
• D. crystallization

Answer 1

The correct option is A

decantation

The explanation for the correct option -

• Option A is correct because Decantation is the process of separating liquid from solid and other immiscible (non-mixing) liquids by removing the liquid layer on top from the solid or liquid layer beneath.
• Since sand particles are insoluble in water, they settle down when the sand solution is kept to stand for some time.
• Now, the top layer of a pure liquid is poured out by slightly tilting the beaker.

The explanation for the incorrect options -

• Option B is incorrect because evaporation is a technique of converting a liquid into its vapors even before its boiling point.
• Option C is incorrect because filtration is a process of separating an insoluble solute from its solution.
• Option D is incorrect because crystallization is the process of cooling a heated, concentrated solution of a chemical to form crystals.

Hence, Option A is the correct answer.