If the solute dissociates in solution, then the number of moles of solute is increased by the van 't Hoff factor formula_7, which represents the true number of solute particles for each formula unit. For example, the strong electrolyte MgCl2 dissociates into one Mg2+ ion and two Cl− ions, so that if ionization is complete, i = 3 and formula_8, where formula_9 is calculated with moles of solute i times initial moles and moles of solvent same as initial moles of solvent before dissociation. The measured colligative properties show that "i" is somewhat less than 3 due to ion association.