Thermodynamic studies of the PbS-H2O-O2-CO2-C4H9OCSS−-CrO42− system and potentiometric measurements of the electrode potential of the galena electrode are performed in alkali solutions of potassium bichromate and potassium butyl xanthate. As a result of an analysis of the probable summary half-reactions of the interaction between galena and the chromate and xanthate ions in alkali media while allowing for various oxidation depths of the sulfide sulfur of galena, new dependences are revealed. It is established that the relation between the concentrations of chromate and xanthate ions at which their interaction with the galena surface is thermodynamically equiprobable is independent of the degree of oxidation of sulfide sulfur of the mineral to S0, S2O32−, and SO42−. The dependence of the electrochemical potential on pH and concentration of chromate and xanthate ions in the liquid phase is revealed. The acquired results revealed the potential-determining character of chromate and hydroxide ions on galena.