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Topic: change of redox indicator  (Read 2722 times)

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Offline aaronhkg

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change of redox indicator
« on: March 03, 2011, 06:55:17 PM »
explain why the indicator "ferroin" changes from red to blue at end point of reaction when titrating Fe2+ ions with Ce4+

this redox reaction has two forms:
[Fe(C12H8N2)3]2+ -> [Fe(C12H8N2)3]3+ + e-
deep red                       pale blue
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Offline Borek

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Re: change of redox indicator
« Reply #1 on: March 04, 2011, 03:44:56 AM »
Question is so general and ambiguous you will probably not get any answer.
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Offline aaronhkg

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Re: change of redox indicator
« Reply #2 on: March 04, 2011, 05:33:28 AM »
can you please suggest one of the answers?

I know it is due to oxidation but I don't know why the colour will change from red to blue.
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Offline Borek

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Re: change of redox indicator
« Reply #3 on: March 04, 2011, 06:30:32 AM »
I am afraid I will be not able to help, but at least the situation is much clearer now.

Looks like you need to apply crystal field theory (or ligand FT) to the iron cation...
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