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Chapter 29 Appendix E: Standard Reduction Potentials at 25°C

Half-Reaction E° (V)
Ac3+ + 3e→ Ac −2.20
Ag+ + e→ Ag 0.7996
AgBr + e→ Ag + Br 0.07133
AgCl + e→ Ag + Cl 0.22233
Ag2CrO4 + 2e→ 2Ag + CrO42− 0.4470
AgI + e→ Ag + I −0.15224
Ag2S + 2e→ 2Ag + S2− −0.691
Ag2S + 2H+ + 2e→ 2Ag + H2S −0.0366
AgSCN + e→ Ag + SCN 0.08951
Al3+ + 3e→ Al −1.662
Al(OH)4 + 3e→ Al + 4OH −2.328
Am3+ + 3e→ Am −2.048
As + 3H+ + 3e→ AsH3 −0.608
H3AsO4 + 2H+ + 2e→ HAsO2 + 2H2O 0.560
Au+ + e→ Au 1.692
Au3+ + 3e→ Au 1.498
H3BO3 + 3H+ + 3e→ B + 3H2O −0.8698
Ba2+ + 2e→ Ba −2.912
Be2+ + 2e→ Be −1.847
Bi3+ + 3e→ Bi 0.308
BiO+ + 2H+ + 3e→ Bi + H2O 0.320
Br2(aq) + 2e→ 2Br 1.0873
Br2(l) + 2e→ 2Br 1.066
BrO3 + 6H+ + 5e12Br2 + 3H2O 1.482
BrO3 + 6H+ + 6e→ Br + 3H2O 1.423
CO2 + 2H+ + 2e→ HCO2H −0.199
Ca2+ + 2e→ Ca −2.868
Ca(OH)2 + 2e→ Ca + 2OH −3.02
Cd2+ + 2e→ Cd −0.4030
CdSO4 + 2e→ Cd + SO42− −0.246
Cd(OH)42− + 2e→ Cd + 4OH −0.658
Ce3+ + 3e→ Ce −2.336
Ce4− + e→ Ce3+ 1.72
Cl2(g) + 2e→ 2Cl 1.35827
HClO + H+ + e12Cl2 + H2O 1.611
HClO + H+ + 2e→ Cl + H2O 1.482
ClO + H2O + 2e→ Cl + 2OH 0.81
ClO3 + 6H+ + 5e12Cl2 + 3H2O 1.47
ClO3 + 6H+ + 6e→ Cl + 3H2O 1.451
ClO4 + 8H+ + 7e12Cl2 + 4H2O 1.39
ClO4 + 8H+ + 8e→ Cl + 4H2O 1.389
Co2+ + 2e→ Co −0.28
Co3+ + e→ Co2+ 1.92
Cr2+ + 2e→ Cr −0.913
Cr3+ + e→ Cr2+ −0.407
Cr3+ + 3e→ Cr −0.744
Cr2O7 + 14H+ + 6e→ 2Cr3+ + 7H2O 1.232
CrO42− + 4H2O + 3e→ Cr(OH)3 + 5OH −0.13
Cs+ + e→ Cs −3.026
Cu+ + e→ Cu 0.521
Cu2+ + e→ Cu+ 0.153
Cu2+ + 2e→ Cu 0.3419
CuI2 + e→ Cu + 2I 0.00
Cu2O + H2O + 2e→ 2Cu + 2OH −0.360
Dy3+ + 3e→ Dy −2.295
Er3+ + 3e→ Er −2.331
Es3+ + 3e→ Es −1.91
Eu2+ + 2e→ Eu −2.812
Eu3+ + 3e→ Eu −1.991
F2 + 2e→ 2F 2.866
Fe2+ + 2e→ Fe −0.447
Fe3+ + 3e→ Fe −0.037
Fe3+ + e→ Fe2+ 0.771
[Fe(CN)6]3− + e→ [Fe(CN)6]4− 0.358
Fe(OH)3 + e→ Fe(OH)2 + OH −0.56
Fm3+ + 3e→ Fm −1.89
Fm2+ + 2e→ Fm −2.30
Ga3+ + 3e→ Ga −0.549
Gd3+ + 3e→ Gd −2.279
Ge2+ + 2e→ Ge 0.24
Ge4+ + 4e→ Ge 0.124
2H+ + 2e→ H2 0.00000
H2 + 2e→ 2H −2.23
2H2O + 2e→ H2 + 2OH −0.8277
H2O2 + 2H+ + 2e→ 2H2O 1.776
Hf4+ + 4e→ Hf −1.55
Hg2+ + 2e→ Hg 0.851
2Hg2+ + 2e→ Hg22+ 0.920
Hg2Cl2 + 2e→ 2Hg + 2Cl 0.26808
Ho2+ + 2e→ Ho −2.1
Ho3+ + 3e→ Ho −2.33
I2 + 2e→ 2I 0.5355
I3 + 2e→ 3I 0.536
2IO3 + 12H+ + 10e→ I2 + 6H2O 1.195
IO3 + 6H+ + 6e→ I + 3H2O 1.085
In+ + e→ In −0.14
In3+ + 2e→ In+ −0.443
In3+ + 3e→ In −0.3382
Ir3+ + 3e→ Ir 1.156
K+ + e→ K −2.931
La3+ + 3e→ La −2.379
Li+ + e→ Li −3.0401
Lr3+ + 3e→ Lr −1.96
Lu3+ + 3e→ Lu −2.28
Md3+ + 3e→ Md −1.65
Md2+ + 2e→ Md −2.40
Mg2+ + 2e→ Mg −2.372
Mn2+ + 2e→ Mn −1.185
MnO2 + 4H+ + 2e→ Mn2+ + 2H2O 1.224
MnO4 + 8H+ + 5e→ Mn2+ + 4H2O 1.507
MnO4 + 2H2O + 3e→ MnO2 + 4OH 0.595
Mo3+ + 3e→ Mo −0.200
N2 + 2H2O + 6H+ + 6e→ 2NH4OH 0.092
HNO2 + H+ + e→ NO + H2O 0.983
NO3 + 4H+ + 3e→ NO + 2H2O 0.957
Na+ + e→ Na −2.71
Nb3+ + 3e→ Nb −1.099
Nd3+ + 3e→ Nd −2.323
Ni2+ + 2e→ Ni −0.257
No3+ + 3e→ No −1.20
No2+ + 2e→ No −2.50
Np3+ + 3e→ Np −1.856
O2 + 2H+ + 2e→ H2O2 0.695
O2 + 4H+ + 4e→ 2H2O 1.229
O2 + 2H2O + 2e→ H2O2 + 2OH −0.146
O3 + 2H+ + 2e→ O2 + H2O 2.076
OsO4 + 8H+ + 8e→ Os + 4H2O 0.838
P + 3H2O + 3e→ PH3(g) + 3OH −0.87
PO43− + 2H2O + 2e→ HPO32− + 3OH −1.05
Pa3+ + 3e→ Pa −1.34
Pa4+ + 4e→ Pa −1.49
Pb2+ + 2e→ Pb −0.1262
PbO + H2O + 2e→ Pb + 2OH −0.580
PbO2 + SO42− + 4H+ + 2e→ PbSO4 + 2H2O 1.6913
PbSO4 + 2e→ Pb + SO42− −0.3588
Pd2+ + 2e→ Pd 0.951
Pm3+ + 3e→ Pm −2.30
Po4+ + 4e→ Po 0.76
Pr3+ + 3e→ Pr −2.353
Pt2+ + 2e→ Pt 1.18
[PtCl4]2− + 2e→ Pt + 4Cl 0.755
Pu3+ + 3e→ Pu −2.031
Ra2+ + 2e→ Ra −2.8
Rb+ + e→ Rb −2.98
Re3+ + 3e→ Re 0.300
Rh3+ + 3e→ Rh 0.758
Ru3+ + e→ Ru2+ 0.2487
S + 2e→ S2− −0.47627
S + 2H+ + 2e→ H2S(aq) 0.142
2S + 2e→ S22− −0.42836
H2SO3 + 4H+ + 4e→ S + 3H2O 0.449
SO42− + H2O + 2e→ SO32− + 2OH −0.93
Sb + 3H+ + 3e→ SbH3 −0.510
Sc3+ + 3e→ Sc −2.077
Se + 2e→ Se2− −0.924
Se + 2H+ + 2e→ H2Se −0.082
SiF62− + 4e→ Si + 6F −1.24
Sm3+ + 3e→ Sm −2.304
Sn2+ + 2e→ Sn −0.1375
Sn4+ + 2e→ Sn2+ 0.151
Sr2+ + 2e→ Sr −2.899
Ta3+ + 3e→ Ta −0.6
TcO4 + 4H+ + 3e→ TcO2 + 2H2O 0.782
TcO4 + 8H+ + 7e→ Tc + 4H2O 0.472
Tb3+ + 3e→ Tb −2.28
Te + 2e→ Te2− −1.143
Te4+ + 4e→ Te 0.568
Th4+ + 4e→ Th −1.899
Ti2+ + 2e→ Ti −1.630
Tl+ + e→ Tl −0.336
Tl3+ + 2e→ Tl+ 1.252
Tl3+ + 3e→ Tl 0.741
Tm3+ + 3e→ Tm −2.319
U3+ + 3e→ U −1.798
VO2+ + 2H+ + e→ VO2+ + H2O 0.991
V2O5 + 6H+ + 2e→ 2VO2+ + 3H2O 0.957
W2O5 + 2H+ + 2e→ 2WO2 + H2O −0.031
XeO3 + 6H+ + 6e→ Xe + 3H2O 2.10
Y3+ + 3e→Y −2.372
Yb3+ + 3e→Yb −2.19
Zn2+ + 2e→ Zn −0.7618
Zn(OH)42− + 2e→ Zn + 4OH −1.199
Zn(OH)2 + 2e→ Zn + 2OH −1.249
ZrO2 + 4H+ + 4e→ Zr + 2H2O −1.553
Zr4+ + 4e→ Zr −1.45