Tin-tin sulphide (Sn-SnS) electrode has been prepared. Statistical analysis indicates that this electrode is stable and reproducible. It has been found that the electrode can be used in the quantitative determination of S2− in the presence of foreign ions such as F−, Cl−, Br−, I−, HCO3−, CO32−, SO42−, SO42− and NO3−. The potential of the electrode in the presence of S2− has been measured by setting up the following type of cell: Sn-SnS/S2− (saturated) KCl/Hg2Cl2, Hg. The electrode shows Nernstian response to pS (−log[S2−]) over the range 7·09 to 12·26. The electrode also shows the Nernstian response to pH in the range 7·54 to 11·98 at constant pS. Values ofE0, (∂E0/∂T)P and various thermodynamic functions,viz., ΔG0, ΔH0 and ΔS0 for the electrode reaction, Sn(s)+S2−(aq) ⇌ SnS(s)+2e, have been determined. Besides, the standard free energy of formation (ΔGt0) and solubility product constant (Kap) of SnS in aqueous medium at 25±0·1°C have also been determined.
Volume 134, 2022
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