“Solubility” is defined as the limiting amount of solute
that can dissolve in a solvent under a given set of physical
conditions. The chemical species of interest to us are present
in aqueous solutions as ions. Certain combinations of these
ions lead to compounds, which have low solubility. Once
this capacity or solubility is exceeded the compounds precipitate
from solution as solids. Therefore, precipitation of
solid materials, which may form scale, will occur if: