Quantitative Analysis of Sulfate in Water by Indirect EDTA Titration.

The determination of sulfate concentration in water by indirect EDTA titration is an instructive experiment that is easily implemented in an analytical chemistry laboratory course. A water sample is treated with excess barium chloride to precipitate sulfate ions as BaSO4(s). The unprecipitated barium ions are then titrated with EDTA. Students are exposed to a number of important concepts including chelation, indirect and back titrations, precipitation, and water quality. A variety of adaptations can be made to the procedure to fit the needs of different lab courses, including general chemistry and environmental chemistry.