Standard Potentials of Silver-Silver Bromide Electrode and Thermodynamic Quantities of Hydrobromic Acid in 90 and 95 Mass per Cent 2-Methyl-1-propanol- Water Mixtures

Sa？etak The e.m.f. of the cell: Pt (or Pd), H2(g)/HBr(rn), 90 and 95 mass per cent 2-methyl-1-propanol-water mixturejAgBr, Ag was measured at 288.15,298,15and 308.15K in the HBr molality range 0.003-0.1 mol kg-i. These data together with the values for the ion-pair dissociation constant of H+· Br- were used to determine the standard e.m.f. of the cell at each temperature. The ion-pair dissociation constants of H+. Br- were determined on the basis of conductivity measurements. The standard e.m.f. of the cell were used to calculate the standard thermodynamic quantities for the cell reaction, mean activity coefficients of HBr and standard thermodynamic quantities for HBr transfer from water to the examined mixed solvents. Standard thermodynamic quantities for the association reaction were calculated from the ion-association constants which are reciprocal values of the ion-pair dissociation constants. The standard thermodynamic quantities of transfer are compared with those of other alcohol-water mixtures while those of association reaction are compared with thecretically predicted values