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Why we use eriochrome black T in complexometric titration?

Why we use eriochrome black T in complexometric titration?

Eriochrome Black T is a complexometric indicator that is used in complexometric titrations, e.g. in the water hardness determination process. In its deprotonated form, Eriochrome Black T is blue. It turns red when it forms a complex with calcium, magnesium, or other metal ions.

What is the color change of eriochrome black T in EDTA titration?

EDTA is short for ethylenediaminetetraacetic acid. 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.

What are the advantages of multidentate ligands over their Unidentate counterparts?

– As titrants, multidentate ligands, particularly those having four or six donor groups, have two advantages over their unidentate counterparts. -First, they generally react more completely with cations and thus provide sharper end points. Figure 17-1 Titration curves for complexometric titrations.

Why is Murexide preferred over eriochrome black T in the estimation of nickel using EDTA?

➡️ Murexide is used normally as its blue/purple end point for the tritation is more easily observed. ➡️Also less murexide is needed for titrations, this is a good thing since indicators by and large are weak acids or bases themselves, thus mimising the impact on the titration figures.

Why buffer solution is used in EDTA titration?

A buffer solution is used in EDTA titration because it resists the change in pH. This is because all the reactions between the metal ions and EDTA are pH-dependent.

Why is EDTA an effective complexing agent for metal ions?

EDTA is a versatile chelating agent. It can form four or six bonds with a metal ion, and it forms chelates with both transition-metal ions and main-group ions. EDTA deactivates these enzymes by removing the metal ions from them and forming stable chelates with them.

What happens if pH is not maintained in complexometric titrations?

Answer: EDTA is insoluble in water at low pH because H4Y is predominant in that pH (less than 2). With increasing the pH, each hydrogen ion in the carboxyl groups of EDTA will start to dissociate. …

Which buffer solution is used in EDTA?

In the EDTA method of measuring hardness, EBT (Eriochrome black-T) is used as indicator… And Ammonium buffer is ised as a buffer….

When to use the Eriochrome Black T in titration?

The Eriochrome Black T can be also applied to determine the sum of Ca 2+ and Mg 2+ (at pH 10) (the method also used for the determination of water hardness). Ca 2+ cannot be determined with the use of Eriochrome Black T because the complex CaInd − is too weak to obtain the distinct change of the color at the end point of titration.

What is the role of Eriochrome Black T in the EDTA?

Explain the role of Eriochrome Black –T and ammonia buffer in the EDTA titration. (Dec 2011) (April 1995) Eriochrome Black T indicator is blue in colour. When EBT indicator is added to water sample, it forms a wine red coloured unstable Ca-Mg-EBT complex.

Which is an example of a complexometric titration experiment?

Conical flask, burette, pipette, spatula, buffer solution, eriochrome black T indicator, standard EDTA Solution (0.01M), inhibitor. Indicator Eriochrome Black T becomes wine red in color when binds with metal ions while remain blue in color when free from metal ion.

Which is complex forming ion of Eriochrome Black T?

Eriochrome black T binds with metal ions loosely while EDTA binds with metal ions strongly. So, when all metal ions are bound to EDTA, indicator EBT remain free in the sample and solution turns blue. We can write complex forming ion of EDTA as H2Y2- which it forms in aqueous solution. The reactions of it with metal ions can be written as follows –