Standard Reduction Potentials in Aqueous Solution at 25oC

Acidic Solution

Eo (V)

F2(g) + 2 e–    2 F–(aq)

+2.87

Co3+(aq) + e–    Co2+(aq)

+1.82

Pb4+(aq) + 2 e–    Pb2+(aq)

+1.8

H2O2(aq) + 2 H+(aq) + 2 e–    2 H2O

+1.77

NiO2(s) + 4 H+(aq) + 2 e–    Ni2+ (aq) + 2 H2O

+1.7

PbO2(s) + SO42–(aq) + 4 H+(aq) + 2 e–    PbSO4(s) + 2 H2O

+1.685

Au+(aq) + e–    Au(s)

+1.68

2 HClO(aq) + 2 H+(aq) + 2 e–    Cl2(g) + 2 H2O

+1.63

Ce4+(aq) + e–    Ce3+(aq)

+1.61

NaBiO3(s) + 6 H+(aq) + 2 e–    Bi3+(aq) + Na+(aq) + 3 H2O

+~1.6

MnO4–(aq) + 8 H+(aq) + 5 e–    Mn2+(aq) + 4 H2O

+1.51

Au3+(aq) + 3 e–    Au(s)

+1.5

ClO3–(aq) + 6 H+(aq) + 5 e–    1/2 Cl2(g) + 3 H2O

+1.47

BrO3– + 6 H+(aq) + 6 e–    Br–(aq) + 3 H2O

+1.44

Cl2(g) + 2 e–    2 Cl–(aq)

+1.358

Cr2O72– + 14 H+(aq) + 6 e–    2 Cr3+(aq) + 7 H2O

+1.33

N2H5+(aq) + 3 H+(aq) + 2 e–    2 NH4+(aq)

+1.24

MnO2(s) + 4 H+(aq) + 2 e–    Mn2+(aq) + 2 H2O

+1.23

O2(g) + 4 H+(aq) + 4 e–    2 H2O

+1.229

Pt2+(aq) + 2 e–    Pt(s)

+1.2

IO3–(aq) + 6 H+(aq) + 5 e–    1/2 I2(aq) + 3 H2O

+1.195

ClO4–(aq) + 2 H+(aq) + 2 e–    ClO3–(aq) + H2O

+1.19

Br2(l) + 2 e–    2 Br–(aq)

+1.066

AuCl4– + 3 e–    Au(s) + 4 Cl–(aq)

+1

Pd2+(aq) + 2 e–    Pd(s)

+0.987

NO3–(aq) + 4 H+(aq) + 3 e–    NO(g) + 2 H2O

+0.96

NO3–(aq) + 3 H+(aq) + 2 e–    HNO2(aq) + H2O

+0.94

2 Hg2+(aq) + 2 e–    Hg22+(aq)

+0.92

Hg2+(aq) + 2 e–    Hg(l)

+0.855

Ag+(aq) + e–    Ag(s)

+0.7994

Hg22+(aq) + 2 e–    2 Hg(l)

+0.789

Fe3+(aq) + e–    Fe2+(aq)

+0.771

SbCl6–(aq) + 2 e–    SbCl4–(aq) + 2 Cl–(aq)

+0.75

[PtCl4]2–(aq) + 2 e–    Pt(s) + 4 Cl–(aq)

+0.73

O2(g) + 2 H+(aq) + 2 e–    H2O2(aq)

+0.682

[PtCl6]2–(aq) + 2 e–    [PtCl4]2–(aq) + 2 Cl–(aq)

+0.68

H3AsO4(aq) + 2 H+(aq) + 2 e–    H3AsO3(aq) + H2O

+0.58

I2(s) + 2 e–    2 I–(aq)

+0.535

TeO2(s) + 4 H+(aq) + 4 e–    Te(s) + 2 H2O

+0.529

Cu+(aq) + e–    Cu(s)

+0.521

[RhCl6]3–(aq) + 3 e–    Rh(s) + 6 Cl–(aq)

+0.44

Cu2+(aq) + 2 e–    Cu(s)

+0.337

Hg2Cl2(s) + 2 e–    2 Hg(l) + 2 Cl–(aq)

+0.27

AgCl(s) + e–    Ag(s) + Cl–(aq)

+0.222

SO42–(aq) + 4 H+(aq) + 2 e–    SO2(g) + 2 H2O

+0.2

SO42–(aq) + 4 H+(aq) + 2 e–    H2SO3(g) + H2O

+0.17

Cu2+(aq) +  e–    Cu+(aq)

+0.153

Sn4+(aq) + 2 e–    Sn2+(aq)

+0.15

S(s) + 2 H+(aq) + 2 e–    H2S(aq)

+0.14

AgBr(s) + e–    Ag(s) + Br–(aq)

+0.0713

2 H+(aq) + 2 e–    H2(g) (reference electrode)

0

N2O(g) + 6 H+(aq) + H2O + 4 e–    2 NH3OH+(aq)

-0.05

Pb2+(aq) + 2 e–    Pb(s)

-0.126

Sn2+(aq) + 2 e–    Sn(s)

-0.14

AgI(s) + e–    Ag(s) + I–(aq)

-0.15

[SnF6]2–(aq) + 4 e–    Sn(s) + 6 F–(aq)

-0.25

Ni2+(aq) + 2 e–    Ni(s)

-0.25

Co2+(aq) + 2 e–    Co(s)

-0.28

Tl+(aq) + e–    Tl(s)

-0.34

PbSO4(s) + 2 e–    Pb(s) + SO42–(aq)

-0.356

Se(s) + 2 H+(aq) + 2 e–    H2Se(aq)

-0.4

Cd2+(aq) + 2 e–    Cd(s)

-0.403

Cr3+(aq) + e–    Cr2+(aq)

-0.41

Fe2+(aq) + 2 e–    Fe(s)

-0.44

2 CO2(g) + 2 H+(aq) + 2 e–    (COOH)2(aq)

-0.49

Ga3+(aq) + 3 e–    Ga(s)

-0.53

HgS(s) + 2 H+(aq) + 2 e–    Hg(l) + H2S(g)

-0.72

Cr3+(aq) + 3 e–    Cr(s)

-0.74

Zn2+(aq) + 2 e–    Zn(s)

-0.763

2H2O(l) + 2 e–    H2(g) + 2OH-(aq)

-0.8277

Cr2+(aq) + 2 e–    Cr(s)

-0.91

Mn2+(aq) + 2 e–    Mn(s)

-1.18

V2+(aq) + 2 e–    V(s)

-1.18

Zr4+(aq) + 4 e–    Zr(s)

-1.53

Al3+(aq) + 3 e–    Al(s)

-1.66

H2(g) + 2 e–    2 H–(aq)

-2.25

Mg2+(aq) + 2 e–    Mg(s)

-2.37

Na+(aq) + e–    Na(s)

-2.714

Ca2+(aq) + 2 e–    Ca(s)

-2.87

Sr2+(aq) + 2 e–    Sr(s)

-2.89

Ba2+(aq) + 2 e–    Ba(s)

-2.9

Rb+(aq) + e–    Rb(s)

-2.925

K+(aq) + e–    K(s)

-2.925

Li+(aq) + e–    Li(s)

-3.045

Basic Solution

 

ClO–(aq) + H2O + 2 e–    Cl–(aq) + 2 OH–(aq)

0.89

OOH–(aq) + H2O + 2 e–    3 OH–(aq)

0.88

2 NH2OH(aq) + 2 e–    N2H4(aq) + 2 OH–(aq)

0.74

ClO3– (aq) + 3 H2O + 6 e–    Cl–(aq) + 6 OH–(aq)

0.62

MnO4–(aq) + 2 H2O + 3 e–    MnO2(s) + 4 OH–(aq)

0.588

MnO4–(aq) + e–    MnO42–(aq)

0.564

NiO2(s) + 2 H2O + 2 e-    Ni(OH)2(s) + 2 OH–(aq)

0.49

Ag2CrO4(s) + 2 e–    2 Ag(s) + CrO42–(aq)

0.446

O2(g) + 2 H2O + 4 e–    4 OH–(aq)

0.4

ClO4–(aq) + H2O + 2e–    ClO3–(aq) + 2 OH–(aq)

0.36

Ag2O(s) + H2O + 2e–    2 Ag(s) + 2 OH–(aq)

0.34

2 NO2–(aq) + 3 H2O + 4 e–    N2O(g) + 6 OH–(aq)

0.15

N2H4(aq) + 2 H2O + 2 e–    2 NH3(aq) + 2 OH–(aq)

0.1

[Co(NH3)6]3+(aq) + e–    [Co(NH3)6]2+(aq)

0.1

HgO(s) + H2O + 2e–    Hg(l) + 2 OH–(aq)

0.0984

O2(g) + H2O + 2 e–    OOH–(aq) + OH–(aq)

0.076

NO3–(aq) + H2O + 2 e–    NO2–(aq) + 2 OH–(aq)

0.01

MnO2(s) + 2 H2O + 2 e–    Mn(OH)2(s) + 2 OH–(aq)

-0.05

CrO42–(aq) + 4 H2O + 3 e–    Cr(OH)3(s) + 5 OH–(aq)

-0.12

Cu(OH)2(s) + 2 e–    Cu(s) + 2 OH–(aq)

-0.36

Fe(OH)3(s) + e–    Fe(OH)2(s) + OH–(aq)

-0.56

2 H2O + 2 e–    H2(g) + 2 OH–(aq)

-0.8277

2 NO3–(aq) + 2 H2O + 2 e–    N2O4(g) + 4 OH–(aq)

-0.85

Fe(OH)2(s) + 2 e–    Fe(s) + 2 OH–(aq)

-0.877

SO42–(aq) + H2O + 2 e–    SO32–(aq) + 2 OH–(aq)

-0.93

N2(g) + 4 H2O + 4 e–    N2H4(aq) + 4 OH–(aq)

-1.15

[Zn(OH)4]2–(aq) + 2 e–    Zn(s) + 4 OH–(aq)

-1.22

Zn(OH)2(s) + 2 e–    Zn(s) + 2 OH–(aq)

-1.245

[Zn(CN)4]2–(aq) + 2 e–    Zn(s) + 4 CN–(aq)

-1.26

Cr(OH)3(s) + 3 e–    Cr(s) + 3 OH–(aq)

-1.3

SiO32–(aq) + 3 H2O + 4 e–    Si(s) + 6 OH–(aq)

-1.7