Determination of the association constant of NaS2O 3 − with the sodium-selective electrode and UV spectrophotometry

The association constant of NaS₂O ₃ ^? complex in a medium of μ=1.0M at 25.0±0.1°C was determined by two techniques: sodium-selective electrode (β₁ = 1.48 ± 0.13) and UV spectrophotometry (β₁ = 1.25 ± 0.10). There is no evidence, under our experimental conditions, of the existence of the binuclear complex Na₂S₂O₃, which might exist at the very low value of the ratio \(C_{Na_2 s_2 o_3 } /C_{Na} +\) used in our experiments.