INTRODUCTION

Solutes may differ in both the extent and the rate at which they dissolve in a solvent. Solubility is the capacity of the solvent to dissolve a solute whereas dissolution rate is how quickly the solubility limit is reached. Equilibrium solubility is the concentration limit, at thermodynamic equilibrium, to which a solute may be uniformly dissolved into a solvent when excess solid is present. The apparent solubility may be either higher or lower than the equilibrium solubility due to transient supersaturation or incomplete dissolution due to insufficient time to reach equilibrium. Equilibrium can be defined as sufficiently converged when it no longer changes significantly during a certain time frame. Solubility may be stated in units of concentration such as molality, molarity, mole fraction, mole ratio, weight/volume, or weight/weight.