Determination of Sulphate by Thermometric Titration
Determination of Sulphate in Sulphuric acid and Contaminated Phosphoric Acid
This application note describes the determination of sulfate by thermometric titration with barium chloride (BaCl2) for two different samples: sulfuric acid of unknown concentration and phosphoric acid contaminated with sulfate.
Background:
Sulfate ions can be determined by titrating with a solution of barium chloride. The formation of the insoluble barium sulfate precipitate is a strong exothermic reaction that can be followed by thermometric titration.
In thermometric titration, the change in reaction heat (i.e. enthalpy change) is monitored in the course of a titration. Thermometric titration allows for an accurate and fast determination of sulfate in various samples. It can be fully automated with an autosampler and the thermometric sensor.
In the given method, the temperature rise corresponds to the exothermic formation of the barium sulfate precipitate. Following reaction takes place during the titration.
Reaction:
SO42- + BaCl2 → BaSO4↓ + 2 Cl-
The Thermotrode™ is suitable for the measurement of small temperature differences induced by the chemical reaction and thus gives precise and accurate results.
Related applications :
Titer Determination of Barium Chloride and Blank Value by Thermometric Titration
