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Topic: Nernst equation and Fe3+/Fe2+ ratio help  (Read 977 times)

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Offline mburn

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Nernst equation and Fe3+/Fe2+ ratio help
« on: October 24, 2019, 08:31:02 PM »
Hello! We've been given this problem

Show that when pH = 5.5  [Fe3+]/[Fe2+] = 200
Given E°(O2/H2O) = 1.23 V
Eº (Fe3+/Fe2+) = 0.77 V
And Ecell=0.46V

I think I know roughly what to do but am a bit confused, because doesn't the E° of this equation also equal 0.46V so any reaction quotient will come out as equal to zero? Or am I misunderstanding something?

Thank you very much

Offline Borek

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Re: Nernst equation and Fe3+/Fe2+ ratio help
« Reply #1 on: October 25, 2019, 02:44:51 AM »
doesn't the E° of this equation also equal 0.46V

Of which equation?

Quote
any reaction quotient will come out as equal to zero

Reaction quotient calculated from the Nernst equation can never be zero.
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