Half-cell Reactions (2) S.J.T.U. Phase Transformation and Applications Table 6.1 Standard Oxidation Potentials Electrode Reaction at 298 K E(V) △G°=-E°zF Acid Solutions Li→Li*+e 3.045 K→K++e 2.925 Cs→Cs++e 2.923 E0>0 Ba→Ba2++2e 2.90 Operate Ca→Ca2++2e 2.87 NaNa +e 2.714 Mg→Mg2++2e 2.37 VG0<0 spontaneously Al→A13++3e 1.66 Zn→Zn2++2e 0.763 Fe→Fe2++2e 0.440 C2+→Cr3++e 0.41 Cd→Cd++2e 0.403 Reference point Sn→Sn2++2e 0.136 Pb→Pb2++2e 0.126 The standard hydrogen electrode Fe→Fe2++3e 0.036 H2→2H++2e 0.000 Cut→Cu2++e -0.153 Cu→Cu2++2e -0.337 Which have a zero voltage when 2I→12+2e -0.5355 Fe2+→Fe3++e -0.771 Ag→Ag++e -0.7991 the reactant,hydrogen and Hg→Hg2++2e -0.854 2Br→Br2(I)+2e -1.0652 product,hydrogen ions,are in C1-→Cl2+e -1.3595 Source:W.M.Latimer,The Oxidation States of the Ele- their standard states (1 mol /L) ments and Their Potentials in Aqueous Solutions,(2nd ed.,Prentice-Hall,Englewood Cliffs.NJ.1952). SJTU Thermodynamics of Materials Springl2o08©X.J.Jin Lecture 11 Electrochemistry llPhase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Springl 2008 © X. J. Jin Lecture 11 Electrochemistry II Half-cell Reactions (2) 0 0 E > 0 0 G <∇ Operate spontaneously Reference point The standard hydrogen electrode Which have a zero voltage when the reactant, hydrogen and product, hydrogen ions, are in their standard states (1 mol / L). zFEGo o −=Δ