calculation from literature values with standard SSA and SSD at ionic strength of 1M, log K for Aerosil in brackets for Cabosil content »Si-OH2<1+> + Br<1-> = »Si-OH2-Br logK = 1.6(1.2) »Si-OH + H<1+> = »Si-OH2<1+> - pK1 = logK = -1.4 sum »Si-OH + Br<1->+ H<1+> = »Si-OH2-Br logK= 1.6(1.2)-1.4 = 0.2(-0.2)