Silver Chloride Electrode - Elevated Temperature Application

Elevated Temperature Application

When appropriately constructed, the silver chloride electrode can be used up to 300 °C. The standard potential (i.e., the potential when the chloride activity is 1 mol/kg) of the silver chloride electrode is a function of temperature as follows:

Bard et al. give the following correlations for the standard potential of the silver chloride electrode as a function of temperature (where t is temperature in °C):

E0(V) = 0.23695 - 4.8564x10−4t - 3.4205x10−6t2 - 5.869 x 10−9t3 for 0 < t < 95 °C.

The same source also gives the fit to the high-temperature potential, which reproduces the data in the table above:

E0(V) = 0.23735 - 5.3783x10−4t - 2.3728x10−6t2 for 25 < t < 275 °C.

The extrapolation to 300 °C gives E0 of -0.138 V.

Farmer gives the following correlation for the potential of the silver chloride electrode with 0.1 mol/kg KCl solution, accounting for the activity of Cl- at the elevated temperature:

E0.1 mol/kg KCl(V) = 0.23735 - 5.3783x10−4t - 2.3728x10−6t2 + 2.2671x10−4(t+273) for 25 < t < 275 °C.