Question

A mixture of water and NaCl can be separated by?
(A) Sublimation
(B) Evaporation
(C) Decantation
(D) Filtration

Answer 1

Hint: We should know the definition of sublimation, evaporation, decantation and filtration in order to solve this question. The boiling point of the sodium chloride is more than the boiling point of the water.

Complete step by step answer:
Option A is sublimation. The sublimation separation technique is a method to separate the components of a mixture by heating, where one of the components is a volatile solid that can sublime and the other is non volatile impurity that remains as such. The sublimed component is then collected. This process is not applicable to separate sodium chloride from water. As the sodium chloride has a higher boiling point than water, so on heating water will get vaporized easily. We need sodium chloride not the water. Therefore, option A is the wrong answer. Option B is evaporation. The evaporation separation technique is the method to separate the components of mixture by heating, where the component that has a less boiling point gets evaporated and the component that has the highest boiling point will be yielded separately. The water has less boiling point so on heating it evaporates easily and the sodium chloride which has a higher boiling point than water remains in the container at least till all the water molecules get evaporated. Therefore, option B is the correct answer. Option C is decantation. This is the method of separating the immiscible liquid floating on other liquid or solid by patiently taking out the floating liquid. From the definition we can make out that this is not the correct answer as sodium chloride is soluble in water. Therefore, option C is the wrong answer. Option D is filtration. This technique is used to remove or separate insoluble residue from liquid. We know that sodium chloride is soluble in water. Therefore, option D is the wrong answer.

Thus the option B is the correct answer.

Note: It is very important to know the methods mentioned above to remember. The example of each of above mentioned techniques are:
- Sublimation: The separation of sodium chloride from camphor.
-Evaporation: The separation of sodium chloride from water.
- Decantation: The separation of water floating on oil.
-Filtration: The separation of sand from water.