The electrode potential has been estimated to be similar to that of the ytterbium ( III ) / ( II ) couple, or about " 1.15 V with respect to the standard hydrogen electrode, a value which agrees with theoretical calculations.
32.
An operational assumption for determinations of the electrode potentials with the standard hydrogen electrode involves this reference electrode with hydrogen ion in an ideal solution having is " zero potential at all temperatures " equivalently to standard enthalpy of formation of hydrogen ion is also " zero at all temperatures ".
33.
Where \ Delta ^ \ text { w } _ o \ phi ^ \ ominus _ \ text { ET } is the standard redox potential for the interfacial transfer of electrons defined as the difference the standard redox potentials of the two redox couples but referred to the aqueous standard hydrogen electrode ( SHE ).
34.
According to the Gibbs-Stockholm convention ( 2 ), the sign of the electrode potential is determined by the polarity of the cell terminal measured against the standard hydrogen electrode using an instrument for DC-potential measurements, when this circuit is closed and balanced ( i . e ., the current on the measurement circuit is nil ).
35.
The standard electrode potential E 0 against standard hydrogen electrode ( SHE ) is 0.230V ?10mV . The potential is however very sensitive to traces of bromide ions which make it more negative . ( The more exact standard potential given by an IUPAC review paper is + 0.22249 V, with a standard deviation of 0.13 mV at 25 �C .)
