•

•                 [(RSO3-)x Mx+]s            Cs

•   K  =  ---------------------  =  -----

•                   [Mx+]xaq                    CM

•

•K turns out to be a distribution ratio (partition)

•

•Order of affinity for sulfonated cation exchange

•Tl+>Ag+>Cs+>Rb+>K+>NH4+>Na+>H+>Li+