Which of these can be used to remove soluble impurities from water?
A. Decantation
B. Distillation
C. Filtration
D. Sedimentation
The correct answer and explanation is:
The correct answer is B. Distillation.
Distillation is a process that separates components of a mixture based on differences in their boiling points. When water contains soluble impurities, such as salts or dissolved minerals, these impurities usually have much higher boiling points than pure water. During distillation, the water is heated until it boils and turns into steam. The steam rises and leaves behind the soluble impurities because they do not vaporize at the boiling temperature of water. The steam is then cooled and condensed back into liquid water, which is purified and free of most soluble impurities.
Decantation is a method used to separate immiscible liquids or solids from liquids by carefully pouring off the liquid without disturbing the solid or heavier liquid. It is not effective for removing soluble impurities because these impurities dissolve completely in the water and cannot be separated by simple pouring.
Filtration involves passing a liquid through a filter to remove solid particles. This method is useful for removing insoluble impurities, such as dirt or sand, but it cannot remove dissolved substances because those particles are too small and fully dissolved in the liquid.
Sedimentation is a process where heavier particles settle down to the bottom of a liquid over time. It is mainly used to separate suspended solid particles from liquids. Soluble impurities, being dissolved, do not settle and remain in the water, so sedimentation cannot remove them.
Distillation is therefore the most suitable method to remove soluble impurities from water because it effectively separates the pure water from dissolved substances based on boiling point differences. This technique is widely used in laboratories, industries, and for producing drinking water from contaminated sources.