Standard Reduction Potentials
| Ox + ne1– | Red | ℰ° (V) | |
|---|---|---|---|
| K1+(aq) + e1– |  |
K(s) | –2.92 |
| Na1+(aq) + e1– | |
Na(s) | –2.71 |
| Mg2+(aq) + 2 e1– | |
Mg(s) | –2.36 |
| Al3+(aq) + 3 e1– | |
Al(s) | –1.66 |
| 2 H2O + 2 e1– | |
H2(g)+ 2 OH1–(aq) | –0.83 |
| Zn2+(aq) + 2 e1– | |
Zn (s) | –0.76 |
| Cr3+(aq) + 3 e1– | |
Cr(s) | –0.74 |
| Fe2+(aq) + 2 e1– | |
Fe(s) | –0.44 |
| 2 H2O + 2 e1– | |
H2(g)+ 2 OH1–(aq) | –0.41* |
| PbSO4(s) + 2 e1– | |
Pb(s) + SO42–(aq) | –0.36 |
| Ni2+(aq) + 2 e1– | |
Ni(s) | –0.23 |
| Sn2+(aq) + 2 e1– | |
Sn(s) | –0.14 |
| Pb2+(aq)+ 2 e1– | |
Pb(s) | –0.13 |
| 2 H1+(aq) + 2 e 1– | |
H2(g) | 0.00 |
| Cu2+(aq) + 2 e1– | |
Cu(s) | +0.34 |
| O2(g) + 2 H2O + 4 e1– | |
4 OH1–(aq) | +0.40 |
| I2(s) + 2 e1– | |
2 I1–(aq) | +0.54 |
| Fe3+(aq) + e1– | |
Fe2+(aq) | +0.77 |
| Ag1+(aq) + e1– | |
Ag(s) | +0.80 |
| O2(g) + 4 H1+(aq) + 4 e1– | |
2 H2O | +0.82* |
| NO31–(aq) + 4 H1+(aq) + 3 e1– | |
NO(g) + 2 H2O | +0.96 |
| Br2(l) + 2 e1– | |
2 Br1–(aq) | +1.09 |
| O2(g) + 4 H1+(aq) + 4 e1– | |
2 H2O | +1.23 |
| Cr2O72–(aq) + 14 H1+(aq) + 6 e1– | |
2 Cr3+(aq) + 7 H2O | +1.33 |
| Cl2(g) + 2 e1– | |
2 Cl1–(aq) | +1.36 |
| MnO41–(aq) + 8 H1+(aq) + 5 e1– | |
Mn2+(aq) + 4 H2O | +1.51 |
| PbO2(s) + 4 H1+(aq) + SO42–(aq) + 2 e1– | |
PbSO4(s) + 2 H2O | +1.69 |
| F2(g) + 2 e1– | |
2 F1–(aq) | +2.87 |
Standard Reduction Potentials at 25 °C in Volts
* The half-cell potentials for the O2/H2O and the H2O/H2 systems are for pure water and are not for standard reduction potentials where [OH1-] and [H1+] = 1.0 M.