Standard electrode potentials  

These notes were written for the old IB syllabus (2009). The new IB syllabus for first examinations 2016 can be accessed by clicking the link below.

IB syllabus for first examinations 2016

 

Standard Electrode Potentials in Aqueous Solution at 25C

(Reduction)
Half-Reaction
Standard Potential
E (volts)
Li+(aq) + e- Li(s)
-3.04
K+(aq) + e- K(s)
-2.92
Ca2+(aq) + 2e- Ca(s)
-2.76
Na+(aq) + e- Na(s)
-2.71
Mg2+(aq) + 2e- Mg(s)
-2.38
Al3+(aq) + 3e- Al(s)
-1.66
2H2O(l) + 2e- H2(g) + 2OH-(aq)
-0.83
Zn2+(aq) + 2e- Zn(s)
-0.76
Cr3+(aq) + 3e- Cr(s)
-0.74
Fe2+(aq) + 2e- Fe(s)
-0.41
Cd2+(aq) + 2e- Cd(s)
-0.40
Ni2+(aq) + 2e- Ni(s)
-0.23
Sn2+(aq) + 2e- Sn(s)
-0.14
Pb2+(aq) + 2e- Pb(s)
-0.13
Fe3+(aq) + 3e- Fe(s)
-0.04
2H+(aq) + 2e- H2(g)
0.00
Sn4+(aq) + 2e- Sn2+(aq)
0.15
Cu2+(aq) + e- Cu+(aq)
0.16
ClO4-(aq) + H2O(l) + 2e- ClO3-(aq) + 2OH-(aq)
0.17
AgCl(s) + e- Ag(s) + Cl-(aq)
0.22
Cu2+(aq) + 2e- Cu(s)
0.34
ClO3-(aq) + H2O(l) + 2e- ClO2-(aq) + 2OH-(aq)
0.35
IO-(aq) + H2O(l) + 2e- I-(aq) + 2OH-(aq)
0.49
Cu+(aq) + e- Cu(s)
0.52
I2(s) + 2e- 2I-(aq)
0.54
ClO2-(aq) + H2O(l) + 2e- ClO-(aq) + 2OH-(aq)
0.59
Fe3+(aq) + e- Fe2+(aq)
0.77
Hg22+(aq) + 2e- 2Hg(l)
0.80
Ag+(aq) + e- Ag(s)
0.80
Hg2+(aq) + 2e- Hg(l)
0.85
ClO-(aq) + H2O(l) + 2e- Cl-(aq) + 2OH-(aq)
0.90
2Hg2+(aq) + 2e- Hg22+(aq)
0.90
NO3-(aq) + 4H+(aq) + 3e- NO(g) + 2H2O(l)
0.96
Br2(l) + 2e- 2Br-(aq)
1.07
O2(g) + 4H+(aq) + 4e- 2H2O(l)
1.23
Cr2O72-(aq) + 14H+(aq) + 6e- 2Cr3+(aq) + 7H2O(l)
1.33
Cl2(g) + 2e- 2Cl-(aq)
1.36
Ce4+(aq) + e- Ce3+(aq)
1.44
MnO4-(aq) + 8H+(aq) + 5e- Mn2+(aq) + 4H2O(l)
1.49
H2O2(aq) + 2H+(aq) + 2e- 2H2O(l)
1.78
Co3+(aq) + e- Co2+(aq)
1.82
S2O82-(aq) + 2e- 2SO42-(aq)
2.01
O3(g) + 2H+(aq) + 2e- O2(g) + H2O(l)
2.07
F2(g) + 2e- 2F-(aq)
2.87