Question

Which of the following mixtures cannot be separated by fractional distillation? (a)Acetone and methyl alcohol (b)Chloroform and Benzene(c) 5% water and 95% ethyl alcohol(d) Benzene and toluene

Answer 1

Answer:

benzene and toluene.. option (d)

Answer 2

Answer:

The correct option to the question-" Which of the following mixtures cannot be separated by fractional distillation? is-

(d) Benzene and toluene

Explanation:

Correct option is D)

Aromatic compound generally separated by fractional distillation.

e.g. Benzene+Toluene.

Fractional distillation

Fractional distillation  is the separation of miscible liquids ,it is a type of distillation . The process involves repeated distillations and condensations and the mixture is usually separated into component parts.

Acetone and methyl alcohol

Fractional distillation is employed for a separating mixture of two or more volatile liquids having boiling point difference approx less than 25-30 DEGREE C. Acetone has a boiling point 600C, whereas methanol has a boiling point of 650C. Hence, it can be separated by fractional distillation.

Chloroform and Benzene

Fractional Distillation is the process from which we separate them. We used one property and which is the difference in their boiling point. So,  we will use distillation to separate benzene and chloroform.

5% water and 95% ethyl alcohol

All the azeotropes boils off then only 95 % ethanol boils. This azeotrope boil at 78.15 0C, which is lower than pure ethanol boiling point, 78.3 0C.,  This work is highly impossible, so we never purify the mixture containing 95 % ethanol and water.

Therefore, we can say that ,Benzene and toluene  are the mixtures which cannot be separated by fractional distillation.