Question

For a non-ideal solution, explain why `V_"mixing" ne 0`.

Answer 1

In a non-ideal solution, the volume of mixing `V_"mixing"`is not equal to zero because the intermolecular interactions between solute and solvent are not the same as those in the pure components.

`V_"mixing" = V_"solution" - (V_"solute" + V_"solvent")`

For ideal solutions `V_"mixing" = 0`

Because the intermolecular forces between the various components (A-B) are distinct from those within the purified components (A-A or B-B), the volume change upon mixing `(ΔV_"mix")` is not zero in non-ideal solutions. The molecules modify their packing arrangements to accommodate the new interactions, resulting in a change in volume during the mixing process as a result of the difference in intermolecular forces.