Non-Ideal Solution Showing Positive Deviation

Introduction:
When two substances are mixed to form a solution, their behavior can deviate from the ideal behavior of a solution. A non-ideal solution can exhibit either positive or negative deviation from ideal behavior. In a non-ideal solution showing positive deviation, the enthalpy of the solution is higher than that predicted by Raoult's law. This means that the interactions between the molecules of the components in the solution are stronger than the interactions between like molecules.

Explanation:
Among the given options, acetone and carbon disulphide (option A) is an example of a non-ideal solution showing positive deviation. Let's understand why:

Acetone:
Acetone, also known as propanone, is a polar solvent. It contains a carbonyl group, which gives it partial positive and negative charges. Acetone can form hydrogen bonds with other polar substances.

Carbon Disulphide:
Carbon disulphide is a nonpolar solvent. It consists of carbon and sulfur atoms bonded by a double bond. It does not have partial charges and cannot form hydrogen bonds.

Interactions:
When acetone and carbon disulphide are mixed, the polar acetone molecules can form dipole-dipole interactions with each other and with the nonpolar carbon disulphide molecules. These interactions are stronger than the interactions between like molecules (acetone-acetone and carbon disulphide-carbon disulphide). As a result, the enthalpy of the solution is higher than what would be predicted by Raoult's law.

Positive Deviation:
Positive deviation occurs when the interactions between the components of the solution are stronger than the interactions between like molecules. In this case, the interactions between acetone and carbon disulphide are stronger than the interactions between acetone-acetone and carbon disulphide-carbon disulphide.

Conclusion:
In conclusion, option A, acetone and carbon disulphide, is an example of a non-ideal solution showing positive deviation. The polar nature of acetone and nonpolar nature of carbon disulphide lead to stronger interactions between the components, resulting in positive deviation from ideal behavior.