Question

How will you separate sand and water from their mixture?

Answer 1

Hint: We should always remember whether a substance will dissolve in another substance or not. If it dissolves, then it will give a clear solution whereas if it does not dissolve, it will form a suspension and the methods employed for separation will become easier. Sand is insoluble in water.

Complete step by step solution:
First let us look into the nature of sand. Sand can have varying colours depending on its location. It can be black, white, green or even pink. Silicon dioxide also called quartz is the most common component of sand. The formation of sand involves the weathering process in which the rocks and minerals are broken down by wind, rain and other factors, into smaller granular particles.
The most common component of sand; quartz is insoluble in water and is quite resistant to decomposition. It gets carried away by streams, rivers and winds to the seashore which leads to the formation of beach sand.
Since sand is insoluble in water, it can be separated from water by employing the following techniques:
-When sand is added to water, it forms a suspension and collects at the bottom of the container if left undisturbed. This is called sedimentation. After all the sand has settled down, we can simply decant off the water in another container.
-If we do not want to wait for the sedimentation process, then we can simply filter the mixture containing sand and water by using a good quality filter paper.
-Though unnecessary and an expensive method than the other two mentioned above, we can also do steam distillation of the mixture containing sand and water. The water will simply convert into steam at its boiling point which condenses and is collected in another beaker.
Hence sand can be separated using sedimentation and decantation; filtration or distillation.

Note: Sand also contains salts and other compounds. If the sand contains a salt that is soluble in water, then we cannot separate the salt from water using the first two methods. But, we can separate the salt and water by using distillation.