Question

A non-ideal solution was prepared by mixing $30ml$ chloroform and $50ml$ acetone. The volume of mixture will be:
A.$>80ml$
B.$<80ml$
C.$=80ml$
D.$\ge 80ml$

Answer 1

We know that to solve this question, we have to know about the following things; volume of mixing: when two miscible compounds are mixed, the volume of the resulting solution is always different from the sum of the volume of the components mixed.

Complete answer:
Raoult’s law is stated for the ideal mixtures. But as all mixtures are real in nature, there would be positive and negative deviation from the law depending upon the polarities of the solutions comprising the mixture.
This change in volume of the solution is called the volume of mixing. It happens because all the solutions in practice are non-ideal solutions. Neither pure acetone nor pure chloroform can form intermolecular Hydrogen-bond. Mixture of chloroform and acetone forms an intermolecular Hydrogen-bond. The mixture solution shows negative deviation from Raoult’s law, i.e., it is a non-ideal solution.
When we are mixing the two compounds Hydrogen-bonding occurs between the Hydrogen-atom and an electronegative atom. Thus, by the formation of intermolecular Hydrogen-bond, the intermolecular attraction is increased in the solution than that of pure components. This increased intermolecular attraction reduces their intermolecular spaces and the molecules are more tightly held in the solution.
A mixture of chloroform and acetone shows a negative deviation from Raoult's law. For such a solution $\Delta {{V}_{mixtur}}e<0$or ${{V}_{t}}<\left( 30+50 \right)ml.$

Therefore, the correct answer is Option B.

Note:
Remember that the polarities and the forces between the molecules of the mixture are responsible for deciding the deviation pattern from Raoult's law. Also, when a mixture is formed, it would be impossible to show different deviations within the solutions.