The standard hydrogen electrode potential by conventional at 298 K is taken to be 0.00 volts.

This is what I have been taught. It talks about SHE at 298 K, so is the hydrogen electrode potential at a temperature other than 298 kelvin also defined to be zero ? If not, how do we calculate at any other temperature?


1 Answer 1


According to the definition used by IUPAC, the standard electrode potential $E^\circ$ of the standard hydrogen electrode is zero at all temperatures.

For solutions in protic solvents, the universal reference electrode for which, under standard conditions, the standard electrode potential ($\ce{H+}/\ce{H2}$) is zero at all temperatures.

The absolute electrode potential $E^\circ(\mathrm{abs})$, however, depends on temperature. Its value can be calculated from thermodynamic quantities (e.g. $\Delta G^\circ$). The recommended value for $T=298.15\ \mathrm K$ is $E^\circ(\mathrm{abs})=4.44(2)\ \mathrm V$.

  • 1
    $\begingroup$ For those (like me) who have never heard of absolute electrode potential: It uses the free electron in a vacuum as reference point, see e.g. en.wikipedia.org/wiki/Absolute_electrode_potential $\endgroup$
    – Karsten
    Jul 19, 2019 at 17:22
  • $\begingroup$ Wait, if the standard electrode potential is zero at all temperatures, what would the electrical potential be of a cell where each half-cell was at a different temperature? $\endgroup$
    – Curt F.
    Jul 19, 2019 at 20:05

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