Ideal solutions and Non- ideal solutions
- The solutions that obey Raoult’s law over the whole collection of concentration are known as ideal solutions.
- The enthalpy of mixing of the pure components for the formation of the solution is zero. Mathematically, Δmix H = 0.
- This implies that heat is neither absorbed nor evolved during the mixing of components in a solution.
- The volume of mixing of the pure components for the formation of the solution is also zero. Mathematically, Δmix V = 0
- Volume of the entire solution = Sum ofvolumes of the components.
- In case of pure components the intermolecular attractive interactions is of A-A and B-B type.
- In case of binary solutions the intermolecular attractive interactions is of A-A, B-B and A-B type.
- When the intermolecular attractive forces between the A-A and B-B type arenearly equivalent to the intermolecular attractive forces between A-B it results in the formation of ideal
- No solution is perfectly ideal but some solutions are nearlyideal in behaviour. For instance, solution of n-hexane and n-heptane, Bromoethaneand chloroethane, benzene and toluene, etc. exhibits ideal behaviour.
- The solutions that do not obey Raoult’s law over the whole collection of concentration are known as non-ideal solutions.
- The vapour pressure of a non-ideal solution is either higher or lower than predicted by Raoult’s law.
