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Titration with EDTA and Eriochrome black T
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Lisa Torres
Titration with EDTA and Eriochrome black T
Assuming you've used Erichrome Black-T as an indicator, the second your whole solution changes from wine red to blue, as in the moment you realise there is a change in colour, however light it is, that's your end point and you should stop.
Make sure you use a white tile under your conical flask and remember to pause the titration and swirl the flask little bit every now and then as you near the end point. That should even out the colour and make the change noticeable before it's too late.
Assuming you've used Erichrome Black-T as an indicator, the second your whole solution changes from wine red to blue, as in the moment you realise there is a change in colour, however light it is, that's your end point and you should stop.
Make sure you use a white tile under your conical flask and remember to pause the titration and swirl the flask little bit every now and then as you near the end point. That should even out the colour and make the change noticeable before it's too late.
I see, thanks. Could you also explain why this is so? As far as I know ErichromeBlack-T is pink as long as there are metall ions that it can bind to, so while there are pink and blue particles (first change) there whould still be some Calcium not bound to EDTA but to ErioTMore
Im a bit unsure about what your question means but Ill try to answer.Erichrome Black-T is actually blue in colour in its protonated form but turns wine red on complexing. That is why it is imperative to swirl the the contents of the flask, to distribute the reagent evenly so that any colour change is uniform. Its only when the whole solution uniformly turns the lightest blue possible that you must stop. There should be no trace of pink of course, but just like its unadvisable to have a deep phenolpthalein pink while titrating, its the same here. Does this answer your question?More
Assuming you've used Erichrome Black-T as an indicator, the second your whole solution changes from wine red to blue, as in the moment you realise there is a change in colour, however light it is, that's your end point and you should stop.
Make sure you use a white tile under your conical flask and remember to pause the titration and swirl the flask little bit every now and then as you near the end point. That should even out the colour and make the change noticeable before it's too late.
Assuming you've used Erichrome Black-T as an indicator, the second your whole solution changes from wine red to blue, as in the moment you realise there is a change in colour, however light it is, that's your end point and you should stop.
Make sure you use a white tile under your conical flask and remember to pause the titration and swirl the flask little bit every now and then as you near the end point. That should even out the colour and make the change noticeable before it's too late.
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