Electrochemistry Reference Electrodes

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SUMMARY

The discussion focuses on converting electric potential readings from an Ag/AgCl reference electrode to a Reversible Hydrogen Electrode (RHE) system at pH 7. The correct conversion formula is established, with the RHE potential at pH 7 calculated as -0.4137 V. The participants clarify the use of 0.222 V for the Ag/AgCl system instead of 0.197 V, which is relevant for a saturated chloride solution. The importance of sign conventions in electrochemical calculations is emphasized, ensuring accurate potential readings.

PREREQUISITES
  • Understanding of electrochemical reference electrodes, specifically Ag/AgCl and RHE.
  • Familiarity with the Nernst equation and its application in potential calculations.
  • Knowledge of pH effects on electrode potentials.
  • Basic principles of electrochemistry and standard electrode potentials.
NEXT STEPS
  • Research the Nernst equation and its applications in electrochemical systems.
  • Learn about the differences between various reference electrodes, including SHE and RHE.
  • Explore the impact of pH on electrochemical reactions and potential measurements.
  • Investigate common sources of error in electrochemical measurements and how to mitigate them.
USEFUL FOR

Students and professionals in chemistry, particularly those studying electrochemistry, laboratory technicians working with reference electrodes, and researchers involved in potential measurements and electrochemical analysis.

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Homework Statement



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

Homework Equations



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

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 ?
 
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-0.0591*7 is not 0.4137

Not that I am sure about the correct signs, but what you did looks inconsistent.
 
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.
 
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.
 
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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