Question

give the stuctures of indicator used for hardness determination.why it changes color at end point of titration​

Answer 1

Answer:

Explanation:

A blue dye called Eriochrome Black T (ErioT) is used as the indicator. This blue dye also forms a complex with the calcium and magnesium ions, changing colour from blue to pink in the process. The dye–metal ion complex is less stable than the EDTA–metal ion complex.