Question

A miscible mixture of ${{C}_{6}}{{H}_{6}}+CHC{{l}_{3}}$ can be separated by:
(a) sublimation
(b) distillation
(c) filtration
(d) crystallisation

Answer 1

Benzene and chloroform have different melting and boiling points. The differences in these properties can be used in order to separate a mixture of these two liquids.

Complete answer:
Let us consider each option in the question
-Sublimation is the process or change in state of matter from a solid to a gas directly, without converting to a liquid phase. Both benzene and chloroform are liquid at room temperature and the mixture of both is also liquid. Thus, we cannot separate them by sublimation process. Option (a) is wrong.
-Distillation process is a way of separating the components of a liquid mixture by selective boiling and condensation. Benzene and chloroform have different boiling points. Boiling point of benzene is ${{80}^{\circ }}C$ and the chloroform is ${{61.2}^{\circ }}C$. If we distil them by using an oil/water bath kept at around 62 to 65 degree Celsius, chloroform will evaporate at this temperature and it can be condensed and collected. When the temperature increases to 81 degree Celsius benzene will evaporate and can be condensed and collected. So, option (b) is correct.
-Filtration is a separation technique involving a mixture of solid and a fluid. In our case benzene and chloroform both are liquids. So, we cannot use this technique.
-Crystallisation is a separation technique in which one of the components of the mixture is precipitated by treating the mixture with certain reagents. Benzene and chloroform cannot be separated by this method. Option (d) is incorrect.
Thus, a mixture of benzene and chloroform can be separated by distillation process

So, the correct answer is “Option B”.

Note: Only if the boiling points of the components of the mixture are different, distillation process is used. Solid and liquid mixtures with different boiling points can also be separated by distillation process.