Environmental Engineering Reference
In-Depth Information
Figure 2.6
Charge separation at electrode-electrolyte interface.
2.2.3 Standard Hydrogen Electrode Scale
There is no valid practical method to determine the absolute value of the potential
difference existing at the metal-electrolyte interface, i.e., of the single-electrode
potential. Any method of measurement of the potential difference needs a measur-
ing instrument dipped in the electrolyte, which means the introduction of a second
electrode-electrolyte interface. Thus, the measured value is always the potential
difference between the two electrode-electrolyte interfaces.
The difficulty in measuring the value of single-electrode potentials is over-
