As.ppi

SPECIATION
  calculationType                      ht1
  calculationMethod                    1
  mainSpecies                          As
  xmin                                 2.0
  xmax                                 12.0
  ymin                                 -90.0
  ymax                                 0.0
  resolution                           200

PLOT
  plotTitle                            "As-H<sub>2</sub>O-O<sub>2</sub>-H<sub>2</sub>O<br>(dominant species)"
  xtitle                               pH
  ytitle                               "log <i>f </i>O<sub>2</sub>(g)"
  extraText                            "extratextAs.dat"

CHEMISTRY

include ht1.inc                                            # standard 'hunt and track' file

SOLUTION 1
   temp      20
   units     mol/kgw
   As        1e-3                                          # total As
   Na        1e-1                                          # background electrolyte
   Cl        1e-1 charge
END

USE solution 1
EQUILIBRIUM_PHASES 1
   Fix_H+     -<x_axis> NaOH                               # <x_axis> is pH so reverse sign
    -force_equality true
   O2(g)      <y_axis>  0.1
END