Summary

Titration is a volumetric technique widely used in chemistry to determine the concentration of an unknown quantity in a solution. In this experiment you have used the chelating agent, EDTA, to determine the concentration of calcium and magnesium metal ions in water. However, to do this, you have actually performed two titration tasks: the first was to determine or standardise the concentration of EDTA; and the second to use this information to determine the hardness of a river water sample.

A key step in both tasks is that you used a dye (the indicator ErioT) to determine the endpoint of the reaction, and importantly, you also used a buffer to maintain the pH at 10 so that the reaction was targeted at calcium and magnesium metal ions.

Previous: Task 2                                                                                   Next: Quiz