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Chemistry Forums for Students => Inorganic Chemistry Forum => Topic started by: Sona on April 24, 2017, 10:34:10 AM

Title: Cr(III)EDTA titration
Post by: Sona on April 24, 2017, 10:34:10 AM

The log k value of Cr-EDTA complex is
23 • 0, still Cr(III) cannot be titrated with
EDTA directly. Explain

What is the reason of this?

No suitable indicatior is found for Cr(III)  or anything else?

Please help

Title: Re: Cr(III)EDTA titration
Post by: Borek on April 25, 2017, 02:52:35 AM

What characteristics should a reaction used in titration have?

Title: Re: Cr(III)EDTA titration
Post by: Sona on May 03, 2017, 09:43:49 AM

The reaction rate should be high and the complex should be stable. An indicator-Cr(III) cmplex should be available which should have different colors in complexed form and free form and this complex should be less stable than the Cr(III)EDTA complex

Title: Re: Cr(III)EDTA titration
Post by: Borek on May 05, 2017, 11:26:54 AM

Good. I would check kinetics of the complexation reaction. I am not saying that's the case here, but there are definitely cations that react quite slowly with EDTA.