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Homework Help: Electrochemistry Reference Electrodes

  1. Sep 3, 2013 #1
    1. The problem statement, all variables and given/known data

    Change your electric potential readings from a Ag/AgCl system to a RHE (reversible hydrogen electrode) system at pH 7.

    For example, 0.3 V vs Ag/AgCl and -0.1 V vs Ag/AgCl

    2. Relevant equations

    Ag/AgCl 0.222 Volts
    RHE 0 - 0.0591*pH Volts

    3. The attempt at a solution

    RHE at pH 7 = 0.4137 V

    0.3 V vs Ag/AgCl + (0.197 - 0.4137) = 0.08333 V ?
    -0.1 V vs Ag/AgCl + (0.197 - 0.4137) = -0.3167 V ?
  2. jcsd
  3. Sep 5, 2013 #2


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    Staff: Mentor

    -0.0591*7 is not 0.4137

    Not that I am sure about the correct signs, but what you did looks inconsistent.
  4. Sep 5, 2013 #3
    ah yes I forgot to put that negative sign on my post. So RHE at pH 7 = 0.4137 V should really be read as RHE at pH 7 = -0.4137 V
    everything below that assumed that sign was there in the first place.

    Are my signs or thinking inconsistent? I was trying to think of everything in terms of SHE (standard hydrogen electrode), which is marked as 0 V.
  5. Sep 5, 2013 #4


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    Staff: Mentor

    What is 0.197?

    Edit: I mean, I know what it is, I wonder why you used 0.197 on calculations, but you listed 0.222 earlier.
  6. Sep 5, 2013 #5
    I was given 0.222 V.
    0.197 V would be for a saturated chloride solution, ooh, oups, that belongs to a followup problem (not relevant to this thread), I see what you mean now. It should say 0.222 V not 0.197 V
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