standard hydrogen electrode
For solutions in @P04900@ solvents, the universal @R05229@ for which, under standard conditions, the @S05912@ (H+ / H2) is zero at all temperatures. The @A00022@ of the hydrogen electrode under standard conditions can be expressed in terms of thermodynamic quantities by applying a suitable Born–Haber cycle, thus: \[E^{\,\unicode{x26ac}}\left(\text{H}^{+}/\text{H}_{2}\right)\left(\text{abs}\right)=\Delta _{\text{at}}G^{\,\unicode{x26ac}}+\Delta _{\text{ion}}G^{\,\unicode{x26ac}}+\frac{\alpha _{\text{H}^{+}}^{\text{o,S}}}{F}\] where \(\Delta _{\text{at}}G^{\,\unicode{x26ac}}\) and \(\Delta _{\text{ion}}G^{\,\unicode{x26ac}}\) are the atomization and @I03183@ Gibbs energies of H2, \(\alpha _{\text{H}^{+}}^{\text{o,S}}\) is the real potential of H2 in solvent S and \(F\) is the @F02325@. The recommended @A00022@ of the hydrogen electrode is: \[E^{\,\unicode{x26ac}}\left(\text{H}^{+}/\text{H}_{2}\right)^{\text{H}_{2}\text{O}}\left(\text{abs}\right)=(4.44\pm 0.02)\ \text{V}\quad \text{at}\quad 298.15\ \text{K}\]
PAC, 1986, 58, 955. (The absolute electrode potential: an explanatory note (Recommendations 1986)) on page 957 [Terms] [Paper]