ABSTRACT
Sulfate ion is titrated with barium Perchlorate to produce insoluble barium sulfate. A metallochromic indicator, thorin, is added to the sample. The titration of sulfate is conducted in 80% 2-propanol to reduce the solubility of BaSO4. As the titrant is added to the sample, the barium preferentially reacts with sulfate. When all of the sulfate is reacted, barium reacts with the free yellow indicator to form the pink barium-indicator complex, signifying the end-point of the titration (1),(2).
