Question

The substance has boiling point 563K, but it starts decomposing near this temperature.Which type of distillation process is suitable for its purification?
A. Distillation
B. Fractional distillation
C. Steam distillation
D. Distillation under reduced pressure

Answer 1

We have to know which method of separation or purification is used for the purification of different types of mixtures depending on their constituent’s properties (physical or chemical).

Complete step by step answer:
We are given four types of processes for the purification.Let us know which type of purification is used to purify what type of mixtures.
Distillation-This method is used for the purification of liquids which boil without decomposition and contain non-volatile impurities .e.g .,pure water can be obtained from sea water by distillation , mixture of ethers and toluene,benzene and aniline.

Fractional Distillation- Fractional distillation is a process which is used for the separation of miscible liquids. The process involves repeated distillations and condensations and therefore the mixture is typically separated into component parts. The separation happens when the mixture is heated at a certain temperature where fractions of the mixture start to vaporize.

Steam Distillation- Steam Distillation is a process of separation for temperature sensitive substances.It is used for separating miscible liquids depending upon their volatile nature. For instance aromatic compounds e.g, o-nitrophenol and p- nitrophenol. It plays a vital role in some industrial regions. Here no chemical reaction takes place. It is a physical process.
Steam Distillation is a process of separation for temperature sensitive substances.It is used for separating miscible liquids depending upon their volatile nature. For instance aromatic compounds e.g, o-nitrophenol and p- nitrophenol. It plays a vital role in some industrial regions. Here no chemical reaction takes place. It is a physical process.

Distillation under reduced pressure- This process is used for separating those liquids which decompose below their boiling point under reduced pressure , liquid boils at low temperature.Hence, the temperature for decomposition is not reached .Thus this process is known as vacuum distillation.
Hence we can clearly see by studying the use of these different types of purification process ,that the substance given to us which boils at 563K ,but starts decomposing below its boiling point ,can only be separated by Distillation under reduced pressure.
So, the correct answer is “Option D”.

Note: A separation process is a method that converts a mixture or solution of chemical substances into two or more distinct product mixtures.One of results of the separation is better yield in one or more of the initial mixture's constituents. In some cases, a separation may fully separate the mixture into pure constituents.