Question

Copper sulphate dissolved in water can be recovered as solid by:
A. Evaporation
B. Filtration
C. Centrifugation
D. All of the above.

Answer 1

Hint: The molecular formula of copper sulphate is $CuS{{O}_{4}}$ . The color of anhydrous copper sulphate is grey-white and the color of hydrated form of copper sulphate is blue. Copper sulphate is an inorganic chemical and soluble in water.

Complete step by step answer:
- In the question it is given that copper sulphate dissolved in water and we have to find how we can recover copper sulphate as solid by using the given options.
- Coming to given options, option A is Evaporation. It is a method used to remove a soluble solid from the water. Coming to present case copper sulphate is in water in the form of copper sulphate solution. By evaporation the water present in the solution evaporates by leaving the copper sulphate crystals. So, the option A is correct.
- Coming to option B is filtration. By using filtration we can separate the residue which is not soluble in water. But in case of copper sulphate, copper sulphate is completely soluble in water. So, we cannot separate copper sulphate in water by using filtration. So, option B is wrong.
- Coming to option C Centrifugation. It is a technique used to remove light weight insoluble chemicals from water. But copper sulphate is completely soluble in water. So, we cannot separate copper sulphate from water by using centrifugation. So, option C is also wrong.
- Therefore by using evaporation only we can separate copper sulphate from water.
So, the correct answer is “Option A”.

Note: The copper sulphate is blue in color in water. Once we separate water from copper sulphate by using evaporation the copper sulphate loses its color and becomes grey-white in color. Means the blue color to the copper sulphate solution comes because of the presence of water.