Eriochrome Black-T (EBT) is an azo compound, carcinogenic in nature. It is mainly used as an indicator in complexometric titrations for the determination of total hardness of water due to elements like calcium, zinc, magnesium and other metal ions.Click to see full answer. In this regard, why we use EBT indicator in complexometric titration?Eriochrome black T is used as an indicator for complexometric titrations because it forms a complex with calcium, magnesium and other metal ions in its protonated form. When titrated with EDTA, the metal ions complexed with eriochrome black T reacts with the EDTA forming a blue solution.Secondly, how do I get an EBT indicator solution? (i) the solution of indicator is prepared by dissolving 1 g of Eriochrome Black T in 15 ml of trienthanol amine and adding 5 ml of absoluta alcohol. It can also be prepared by dissolving 0.2 g of Eriochrome Black T in 20 ml of absolute alcohol. Use about 3 to 4 drops of the indicator solution. Additionally, what is the Colour of EBT indicator? EBT is blue in a buffered solution ( an aqueous solution consisting of a mixture of a weak acid and its conjugate base, or vice versa) at pH 10. It turns red when Ca2+ ions are added. The ions involved in water hardness, i.e. Ca2+(aq) and Mg2+(aq) change the steel blue colour of EBT indicator into wine red colour.What are the indicators used in complexometric titration?Indicators. To carry out metal cation titrations using EDTA, it is almost always necessary to use a complexometric indicator to determine when the end point has been reached. Common indicators are organic dyes such as Fast Sulphon Black, Eriochrome Black T, Eriochrome Red B, Patton Reeder, or Murexide.