P4: Polarographic Half-Wave Potentials
- Page ID
- 6651
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The following table provides E1/2 values for selected reduction reactions. Values are from Dean, J. A. Analytical Chemistry Handbook, McGraw-Hill: New York, 1995.
| Element | E1/2 (volts vs. SCE) | Matrix |
|---|---|---|
| Al3+ + 3e− ⇋ Al(s) | –0.5 | 0.2 M acetate (pH 4.5–4.7) |
| Cd2+ + 2e− ⇋ Cd(s) | –0.60 | 0.1 M KCl 0.05 M H2SO4 1 M HNO3 |
| Cr3+ + 3e− ⇋ Cr(s) | –0.35 (+3 → +2) –1.70 (+2 → 0) |
1 M NH4Cl plus 1 M NH3 1 M NH4+/NH3 buffer (ph 8–9) |
| Co3+ + 3e− ⇋ Co(s) | –0.5 (+3 → +2) –1.3 (+2 → 0) |
1 M NH4Cl plus 1 M NH3 |
| Co2+ + 2e− ⇋ Co(s) | –1.03 | 1 M KSCN |
|
Cu2+ + 2e− ⇋ Cu(s) |
0.04 –0.22 |
0.1 M KSCN 0.1 M NH4ClO4 1 M Na2SO4 0.5 M potassium citrate (pH 7.5) |
| Fe3+ + 3e− ⇋ Fe(s) | –0.17 (+3 → +2) –1.52 (+2 → 0) |
0.5 M sodium tartrate (pH 5.8) |
|
Fe3+ + e− ⇋ Fe2+ |
–0.27 | 0.2 M Na2C2O4 (pH < 7.9) |
| Pb2+ + 2e− ⇋ Pb(s) | –0.405 –0.435 |
1 M HNO3 1 M KCl |
| Mn2+ + 2e− ⇋ Mn(s) | –1.65 | 1 M NH4Cl plus 1 M NH3 |
| Ni2+ + 2e− ⇋ Ni(s) |
–0.70 |
1 M KSCN 1 M NH4Cl plus 1 M NH3 |
|
Zn2+ + 2e− ⇋ Zn(s) |
–0.995 –1.33 |
0.1 M KCl 1 M NH4Cl plus 1 M NH3 |