Question

Azeotropic mixtures are:

• A. mixture of two solids
• B. those which boil at different temperatures
• C. those which can be fractionally distilled
• D. constant boiling mixtures

Answer 1

The correct option is D

constant boiling mixtures

The correct option is (D):

Explanation for the correct answer:

Azeotropic mixture:

1. This is actually a mixture of substances that has the same concentration of vapor and the fluid phase.
2. This mixture consists of two or more liquids and it has the constant boiling points .
3. It is generally formed by the non-ideal solutions that will have the boiling points either greater or smaller than both the components.
4. Non-ideal solution is actually a solution in which the interaction between the molecule is not very close with the interaction between the other molecule of the different components.
5. And this mixture is formed only when it will deviate from the Raoult's law and also the equality of compositions in liquid as well as the vapor phase.
6. Mixture vapor here, will also have the same composition as the liquid.
7. Example for this mixture: Mixture of Ethanol inWater.

Explanation for the incorrect answers:

Option (A):

Mixture of two solids:

1. Azeotropic mixture is not the mixture of two solids.
2. This mixture basically consists of two or more liquids and in the same composition.
3. Hence, this is an incorrect option.

Option (B):

Those which boil at different temperatures:

1. The vapor in the azeotropic mixture has the same proportions of the constituents as the unboiled mixture.
2. And also these mixture boil at a constant temperature.
3. Hence, this is an incorrect option.

Option (C):

Those which can be fractionally distilled:

1. Azeotropic mixture can not be separated into the components by fractional distillation.
2. Basically when the mixture is boiled, it will have the same proportions of the constituents as the unboiled mixture.
3. Hence, this is an incorrect option.

Therefore, the correct option is (D): Constant boiling mixtures.