Question

A mixture of oil and water can be separated by using?

Answer 1

Hint: On seeing the question, the first thing we realize is that oil and water are immiscible. We also know that they have a difference in densities because of which oil floats on water. This can be utilized in separating them.

Complete step by step solution:
Immiscible liquids are those liquids which will not mix with each other to give a single phase. Oil and water are examples of immiscible liquids - one floats on top of the other. For separating immiscible liquids like oil and water we use separating funnels. It is a gas laboratory apparatus used in liquid-liquid extraction.
The principle of separating funnels is that immiscible liquids separate out in layers depending on their densities.
We can separate a mixture of Kerosene oil and water in the following way.
* Pour the mixture of kerosene oil and water in a separating funnel.
* Let it stand undisturbed for sometime so that separate layers of oil and water are formed.
* Open the stopcock of the separating funnel and pour out the lower layer of water carefully.
* Close the stopcock of the separating funnel as the oil reaches the stop-cock.

Note: Sometimes, the two layers do not easily separate due to the formation of an emulsion. In that case, we would have to use a glass rod to agitate the sides of the funnel. This would solve the problem and we can then start our process. Adding an organic solvent decreases the surface tension and aids the process.