SOLVENT POLARITY AND SUPPORTING ELECTROLYTE CONCENTRATION INFLUENCES ON FARADAIC CONDUCTIVITY OF QUINHYDRONE SOLUTIONS

Using micrometer twin-electrode thin-layer cell the heterogeneous redo x reaction of quinhydrone is explored in water and in mixed solvents w ith the ratios of toluene: acetonitrile = 9:1 and 4:6. The concentrati on of the supporting electrolyte is varied from zero to 0.5 mol/L. Sup porting electrolyte decreases the kinetic polarization of electrodes a nd increases the faradaic current until concentration polarization occ urs. In dilute electrolytes, the migration of redox species influences the limiting current significantly. The mechanism of reduction and ox idation of quinhydrone and the conditions required for permanent farad aic conduction are determined empirically.