Which of the following techniques would best be used to separate rice and water? A. Decantation B. Distillation C. Evaporation D. Filtration
The correct answer and explanation is:
The correct answer is A. Decantation.
Decantation is the best technique to separate rice and water because it involves carefully pouring off the liquid from a mixture, leaving the solid particles behind. In this case, rice grains are solid and heavier than water, so after allowing the mixture to settle, the rice will sink or remain at the bottom, and the water can be poured off without disturbing the rice much.
Distillation is a process used to separate liquids based on their boiling points. It is not suitable for separating solid rice from water because rice does not evaporate or boil; only the water would evaporate and condense, leaving rice behind. Distillation is more appropriate for separating mixtures of liquids or purifying a liquid.
Evaporation involves heating a liquid to turn it into vapor, leaving the solid residue behind. While evaporation can separate rice and water, it is less practical because it requires time and energy to evaporate all the water. It might also affect the quality of the rice if heated excessively.
Filtration involves passing a mixture through a filter to separate solids from liquids. Although filtration can separate solid rice grains from water, rice grains are large enough to settle quickly and can be separated without the need for filtration. Filtration is usually more suitable for separating smaller particles or when the solid does not settle easily.
Decantation is simple, fast, and effective for separating rice and water because rice grains are large and heavy enough to settle quickly, making it easy to pour off the water. This method preserves the rice without subjecting it to heat or complicated equipment. Therefore, decantation is the most suitable technique among the options for separating rice and water.