Question

Which of the following statements is/are correct?
(A) Minimum boiling azeotropic mixture boils at a temperature lower than either of the two pure components.
(B) Maximum boiling azeotropic mixture boils at a temperature higher than either of the two pure components.
(C) Minimum boiling azeotropic mixture shows positive deviation.
(D) Maximum boiling azeotropic mixture shows negative deviation.

Answer 1

Hint :The boiling point of pure solvent is different from boiling point of solution. It depends on the nature of the solution , whether an ideal or non-ideal solution. We can take reference of Raoult's Law to describe the positive and negative deviation of mixture.

Complete Step By Step Answer:
A.Minimum boiling azeotropic mixture has lesser interaction between its constituents. Therefore the boiling point of the mixture is low. It becomes lower than the boiling point of either of two pure components because of weak attraction between them.
A mixture of water and ethyl alcohol is a minimum boiling azeotropic mixture.
B. Maximum boiling azeotropic mixture has greater force of attraction between its constituents. Therefore the boiling point of such a mixture now becomes higher than either of the two pure components of the mixture.
A mixture of chloroform and acetone is the maximum boiling azeotropic mixture.
C. In case of minimum boiling azeotropic mixture the volume of mixture is higher than the sum of individuals volume .This is because of less solute solvent attraction. Hence the enthalpy of solution becomes positive. This is because it shows positive deviation.
D. In case of maximum boiling azeotropic mixture the volume of mixture is lower than the sum of individuals volume. This is because of more solute solvent attraction. Hence the enthalpy of solution becomes negative. This is because it shows negative deviation.
The positive and negative deviation can also be understood in terms of vapour pressure .In case of positive deviation vapour pressure of solution becomes higher and in case of negative deviation vapour pressure becomes lower.
Therefore considering all the given options . The answer of question comes to be:
All options are correct.

Note :
Consider the concept of volumes for better understanding of positive and negative deviation of azeotropic mixture. The force of attraction between solute and solvent may be the Hydrogen Bonding ,Dipole Dipole attraction etc.