In cell notation the electrode is written as:
|
The mercury concentration can be calculated from the solubility product
:
The concentration of Cl
- is fixed by the solubility of potassium chloride,
:
The activity of a solid is 1. Two electrons are transferred per Hg
2 dication. The
Nernst Equation thus becomes
:
At standard conditions, the potential of the SCE is +0.244 V versus the
SHE .
The SCE is used in
PH measurement,
Cyclic Voltammetry and general aqueous
Electrochemistry .
This electrode and the
Silver/silver Chloride Reference Electrode work in the same way. In both electrodes, the activity of the metal ion is fixed by the solubility of the metal salt.
The calomel electrode contains mercury, which poses much greater health hazards than the silver metal used in the Ag/AgCl electrode.
