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    Electrode potential

    Also known as single electrode potential,it is the internal potential of the electrode relative to the electrolyte phase surrounding it. The internal potential of the electrode phase is referred to as Ve while Vs is the internal potential of the electrolyte phase. Ve-Vs is the potential difference between them. If, for example, a foreign metal is located in an electrolyte, both have different internal potential values and there is an electrolytic reaction between the two instead, i.e. the so-called galvanic current flows between them. Since the single potential is not directly measurable, a reference electrode will be used (for example a hydrogen electrode) that forms a galvanic cell together with the electrode to be measured. By measuring the voltage between the two poles, the absolute value of the electrode potential can be calculated. The following table provides an overview of various electrode potentials.

    Standard electrode potentials
    Electrode reaction Eo (Volt) Electrode reaction Eo (Volt)
    Li+ +e Li -3,05 V3+ +e V2+ -0,26
    K+ +e K -2,93 Ni2+ +2e Ni -0,25
    Ba2+ +2e Ba -2,91 Sn2+ +2e Sn -0,14
    Ca2+ +2e Ca -2,87 Pb2+ +2e Pb -0,13
    Na+ +e Na -2,71 Fe3+ +3e Fe -0,06
    Mg2+ +2e Mg -2,36 2H+ +2e H2 0,00
    Al3+ +3e Al -1,66 Sn4+ +2e Sn2+ 0,15
    Mn2+ +2e Mn -1,18 Cu2+ +e Cu+ 0,16
    Cr2+ +2e Cr -0,91 Cu2+ +2e Cu 0,34
    Zn2+ +2e Zn -0,76 Cu+ +e Cu 0,52
    Cr3+ +3e Cr -0,74 Fe3+ +e Fe2+ 0,77
    Fe2+ +2e Fe -0,44 Ag+ +e Ag 0,80
    Cr3+ +e Cr2+ -0,41 2Hg2+ +2e Hg22+ 0,91
    Cd2+ +2e Cd -0,40 Br2(aq) +2e 2Br- 1,09
    Ti3+ +e Ti2+ -0,37 Pt2+ +2e Pt 1,20
    Co2+ +2e Co -0,28 Co3+ +e Co2+ 1,81
    Standard electrode potentials