Titer of Na2S2O3 0.1 mol/L

In Potentiometric Titration, the concentration dependent potential (mv) of a solution is measured against a reference potential. The potentiometric principleis most commonly used for automated or semi-automated titrations (manual titration with a sensor and a measuring unit).This includes pH measurements, redox measurements and silver ion measurements. Typically a combined sensor (electrode) including reference is used.

The redox reaction between Sodium thiosulfate with potassium iodate (KIO₃) is used to determine the titer of Na₂S₂O₃ potentiometrically.

Reaction:

KIO₃ + 6Na₂S₂O₃ + 6H⁺ → 3S₄O₆^2- + I^- + K⁺ + 12Na⁺ + 3H₂O

This application is used to standardize Na₂S₂O₃ titrant with potassium iodate (KIO₃). The titration is monitored by potentiometric measurement with a Platinum sensor and the titration curve is evaluated at the inflection point to determine the equivalence point (EQP).