Ideal Solutions – Class 12 | Chapter – 2 | Chemistry Short Notes Series PDF for NEET & JEE
Ideal Solutions: An ideal solution is a homogeneous mixture of two or more substances that obeys Raoult’s law. According to Raoult’s law, the partial vapour pressure of each component in the solution is directly proportional to its mole fraction in the solution.
Properties of Ideal Solutions
An ideal solution is characterized by the following properties:
No interaction between the molecules of the components: The intermolecular forces between the molecules of each component in the solution are identical, which means that there is no attraction or repulsion between them.
No change in volume:The volume of the solution is equal to the sum of the volumes of the individual components. There is no change in volume when the components are mixed together.
No change in enthalpy: There is no heat absorbed or released when the components are mixed together.
No change in entropy:There is no increase or decrease in entropy when the components are mixed together.
Examples of Ideal Solutions
Ideal solutions are rare, but there are some examples of ideal solutions in nature and in laboratories. Here are a few examples:
Mixture of noble gases:Noble gases like helium, neon, argon, krypton, and xenon show ideal behavior when they are mixed together. The intermolecular forces between these gases are negligible, and hence their solutions are ideal.
Solution of benzene and toluene:Benzene and toluene have a similar structure and show similar intermolecular forces. Therefore, when they are mixed together, they form an ideal solution.
Solution of ethanol and water: Ethanol and water are highly miscible, and their solutions show ideal behavior when they are mixed together. This is because of the similarity in the intermolecular forces of ethanol and water molecules.
Solution of hexane and heptane:Hexane and heptane are both hydrocarbons with similar molecular structures. They show similar intermolecular forces, and hence their solutions exhibit ideal behavior.
Solution of methanol and ethanol: Methanol and ethanol are both polar molecules and form an ideal solution when they are mixed together. This is because of their similar intermolecular forces and molecular structure.