Ideal-dilute-incompressible solutions

Solutions are crucial components of natural and technological systems. Two of the classical hypotheses in solution theory are those of ideality and diluteness, which are used in the literature to assign to the solutes an activity equal to that of perfect gases and derive Fick's law of diffusion. Here, we argue that these hypotheses are not sufficient for these purposes. Two more hypotheses are missing: the solution must be incompressible and the volumetric fractions of solutes must be small. We propose to name this new cornerstone of solution theory “ideal-dilute-incompressible” solutions.