Which separation method is used to separate a solid from a liquid, such as sand from water?

• A. Filtration
• B. Distillation
• C. Chromatography
• D. Crystallization

Answer: (A)

Separating a solid from a liquid relies on a barrier that lets the liquid pass through while trapping the solid. Filtration uses a porous barrier, like filter paper or a membrane. When the sand–water mixture is poured through, the water flows through the pores while the sand grains are retained, giving a liquid filtrate and a solid residue on the filter.

This works best when the solid is insoluble or only slightly soluble in the liquid and the solid particles are larger than the filter pores. Distillation, by contrast, separates components based on boiling points and would not remove sand effectively since sand isn’t volatile. Chromatography separates substances by how they interact with a stationary phase and is used for mixtures of dissolved substances, not bulk solids. Crystallization purifies dissolved solutes by forming crystals, not by removing undissolved solids from a liquid.

So, filtration is the appropriate method to separate a solid from a liquid like sand from water.