STUDIES IN THE BEHAVIOUR OF BI-UNIVALENT SALTS IN AQUEOUS SOLUTION. PART III. LEAD ACETATE

Cells of the Hg_x Pb_yI PbAc₂ (C) HAc (cr) II salt bridge II Pb(NO₃)₂ (c) I Hg_x Pb_y were studied earlier and the dissociation constant of PbAc⁺ \(\rightleftharpoons\) Pb⁺⁺+ Ac^- was shown to be 3.1 x 10^-3. Study of cells of the type Hg ǀ Hg₂ Ac₂ǁ PbAc₂ (c) HA (cr) ǁ Salt bridge ǁ NaAc (2c) HAc (cr) Hg₂Ac₂ ǀ Hg showed that lead acetate dissociated into two stages. By combining the results of the above two type of cell it was possible to calculate the two equilibrium constants. The value of k₁ (\(PbAc_2 \rightleftharpoons PbAc^++Ac^-\)) was found to be 3.0 x 10^-2 and that of k₂ (\(PbAc^+\rightleftharpoons Pb^{++}+ Ac^-\)) to be 3.7 x 10^-3. Study of the cells of the type in which there is no liquid junction potential Pb_x Hg_y ǀ PbAc₂ (c) HAc (cr) Hg₂Ac₂ǀ Hg showed that the calculate values of k₁ and k₂ were correct and the salt bridges had been able to eliminate liquid junction potential effectively.