Table F.1 dissociation as a function of pH for bentazone and ioxynil Bentazone Ioxynil pH pKa = 2.92 pKa = 3.96 4 7.68E-02 4.77E-01 5 8.25E-03 8.36E-02 6 8.31E-04 9.04E-03 7 8.32E-05 9.11E-04 8 8.32E-06 9.12E-05 9 8.32E-07 9.12E-06