EDTA Titration of Ca²⁺ and Mg²⁺ in natural water

2021-11-10

EDTA Titration of Ca²⁺ and Mg²⁺ in natural water

In this experiment, the concentrations of Ca²⁺ and Mg²⁺ in natural water samples were determined using EDTA titration. The method relies on complexometric titration, with Eriochrome Black T and hydroxynaphthol blue used as indicators to signal the end points of the titrations. 

To determine the total concentration of Mg²⁺ and Ca²⁺, tap water was titrated with EDTA after adding a pH 10 buffer and Eriochrome Black T. The titration was carried out until the color of the sample matched the blank’s endpoint. This step was repeated to ensure accuracy.

During the Ca²⁺ titration, NaOH was added to the water sample to precipitate Mg(OH)₂, leaving only Ca²⁺ in solution. The titration was then performed with EDTA until the appropriate endpoint color was achieved.

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