Figure 2.

Predicted equilibrium properties of ROMB solutions composed of NaHCO₃ and NaOH. (A) pH and (B) PCO₂ of ROMB solutions resulting from mixing different proportions of a 150 mM NaOH solution to a 150 mM NaHCO₃ solution, expressed by the ratio of the initial concentration of hydroxide ions [OH⁻]₀ divided by the initial concentration of bicarbonate anions [${\text{HCO}}_3^{-}$]₀. The total initial concentration of basic species is fixed at 150 mM. For ratios greater than 1, PCO₂ has a vanishingly small value and is not shown.