where ν i is the stoichiometric coefficient and µ i the chemical potential and µ ⊖ the standard chemical potential of species i. The constant Γ (H + ,OH -) = 10 -14 is the ionic product of water. Two out of the remaining three equilibrium constants, Γ (Na + ,Cl -) , Γ (H + ,Cl -) , Γ (Na + ,OH -) are linearly independent and can be chosen independently as input parameters which define the salt concentration and pH of the supernatant solution.