Preferred Label : standard hydrogen electrode;
IUPAC definition : For solutions in protic solvents, the universal reference electrode for which, under
standard conditions, the standard electrode potential (H sup class plus /sup /
H sub 2 /sub ) is zero at all temperatures. The absolute electrode potential of the
hydrogen electrode under standard conditions can be expressed in terms of thermodynamic
quantities by applying a suitable Born–Haber cycle, thus: \[E {\,\unicode{x26ac}}\left({H}
{ }/{H}_{2}\right)\left({abs}\right) Δ _{{at}}G {\,\unicode{x26ac}} Δ _{{ion}}G {\,\unicode{x26ac}}
\frac{\alpha _{{H} { }} {{o,S}}}{F}\] where Δ at G and Δ ion G are the atomization
and ionization Gibbs energies of H sub 2 /sub , αH o,S is the real potential of H
sub 2 /sub in solvent S and F is the Faraday constant. The recommended absolute electrode
potential of the hydrogen electrode is: \[E {\,\unicode{x26ac}}\left({H} { }/{H}_{2}\right)
{{H}_{2}{O}}\left({abs}\right) (4.44\pm 0.02)\ {V}\quad {at}\quad 298.15\ {K}\];
Origin ID : S05917;
See also
For solutions in protic solvents, the universal reference electrode for which, under
standard conditions, the standard electrode potential (H sup class plus /sup /
H sub 2 /sub ) is zero at all temperatures. The absolute electrode potential of the
hydrogen electrode under standard conditions can be expressed in terms of thermodynamic
quantities by applying a suitable Born–Haber cycle, thus: \[E {\,\unicode{x26ac}}\left({H}
{ }/{H}_{2}\right)\left({abs}\right) Δ _{{at}}G {\,\unicode{x26ac}} Δ _{{ion}}G {\,\unicode{x26ac}}
\frac{\alpha _{{H} { }} {{o,S}}}{F}\] where Δ at G and Δ ion G are the atomization
and ionization Gibbs energies of H sub 2 /sub , αH o,S is the real potential of H
sub 2 /sub in solvent S and F is the Faraday constant. The recommended absolute electrode
potential of the hydrogen electrode is: \[E {\,\unicode{x26ac}}\left({H} { }/{H}_{2}\right)
{{H}_{2}{O}}\left({abs}\right) (4.44\pm 0.02)\ {V}\quad {at}\quad 298.15\ {K}\]
