Ideal Solution
A solution in which the interactions between unlike molecules are identical to those between like molecules, so Raoult's law holds at all compositions.
Formula / equation
ΔH_mix = 0, ΔV_mix = 0
Unit
Dimensionless
In depth
Mixing produces neither heat nor volume change, and the only driving force is the entropy of mixing. Ideal behaviour requires the components to be structurally and energetically very similar, so it is essentially confined to mixtures of close homologues or isotopic variants.
Examples in the real world
Benzene with toluene, hexane with heptane, and bromoethane with iodoethane.