portion of mixture portion of solution The phase (solid, liquid, gas) of the solution is usually the phase of the solvent. William Hogan William Hogan a portion of mixture of two or more portions of pure substances whereby one or more of its pure substance parts called solute(s) is (are) dispersed evenly in another pure substance part called the solvent, whereby (1) the grains of the solvent and solute(s) are of size ≤10^-9m, and (2) the solvent typically has a much greater mass and volume than the solute(s)