16.15: Potenciales polarográficos de media onda
- Page ID
- 75447
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La siguiente tabla proporciona valores de E 1/2 para reacciones de reducción seleccionadas. Los valores son de Dean, J. A. Analytical Chemistry Handbook, McGraw-Hill: Nueva York, 1995.
| Element | \(E_{1/2}\)(voltios frente a SCE) | Matrix |
|---|---|---|
| \(\ce{Al^{3+}}(aq) + \ce{3 e-} \ce{<=>} \ce{Al}(s)\) | \ (E_ {1/2}\) (voltios frente a SCE)” style="vertical-align:middle; ">—0.5 | Acetato 0.2 M (pH 4.5—4.7) |
| \(\ce{Cd^{2+}}(aq) + \ce{2 e-} \ce{<=>} \ce{Cd}(s)\) | \ (E_ {1/2}\) (voltios frente a SCE)” style="vertical-align:middle; ">—0.6 |
0,1 M KCl 0.050 M H 2 SO 4 1 M HNO 3 |
| \(\ce{Cr^{3+}}(aq) + \ce{3 e-} \ce{<=>} \ce{Cr}(s)\) | \ (E_ {1/2}\) (voltios frente a SCE)” style="vertical-align:middle;” class="lt-chem-135882">
—0.35\((+3 \ce{->} +2)\) —1.70\((+2 \ce{->} 0)\) |
1 M NH 4 Cl más 1 M NH 3 1 M NH 4 +/ NH 3 tampón (pH 8—9) |
| \(\ce{Co^{3+}}(aq)+ \ce{3 e-} \ce{<=>} \ce{Co}(s)\) | \ (E_ {1/2}\) (voltios frente a SCE)” style="vertical-align:middle;” class="lt-chem-135882">
—0.5\((+3 \ce{->} +2)\) —1.3\((+2 \ce{->} 0)\) |
1 M NH 4 Cl más 1 M NH 3 |
| \(\ce{Co^{2+}}(aq) + \ce{2 e-} \ce{<=>} \ce{Co}(s)\) | \ (E_ {1/2}\) (voltios frente a SCE)” style="vertical-align:middle; ">—1.03 |
1 M KSCN |
| \(\ce{Cu^{2+}}(aq) + \ce{2 e-} \ce{<=>} \ce{Cu}(s)\) | \ (E_ {1/2}\) (voltios frente a SCE)” style="vertical-align:middle;” class="lt-chem-135882">
0.04 —0.22 |
0.1 M KSCN 0.1 M NH 4 ClO 4 1 M Na 2 SO 4 Citrato de potasio 0.5 M (pH 7.5) |
| \(\ce{Fe^{3+}}(aq) + \ce{3 e-} \ce{<=>} \ce{Fe}(s)\) | \ (E_ {1/2}\) (voltios frente a SCE)” style="vertical-align:middle;” class="lt-chem-135882">
—0.17\((+3 \ce{->} +2)\) —1.52\((+2 \ce{->} 0)\) |
Tartrato de sodio 0.5 M (pH 5.8) |
| \(\ce{Fe^{3+}}(aq) + \ce{e-} \ce{<=>} \ce{Fe^{2+}}(aq)\) | \ (E_ {1/2}\) (voltios frente a SCE)” style="vertical-align:middle; ">—0.27 | 0.2 M Na 2 C 2 O 4 (pH < 7.9) |
| \(\ce{Pb^{2+}}(aq) + \ce{2 e-} \ce{<=>} \ce{Pb}(s)\) | \ (E_ {1/2}\) (voltios frente a SCE)” style="vertical-align:middle;” class="lt-chem-135882">
—0.405 —0.435 |
1 M HNO 3 1 M KCl |
| \(\ce{Mn^{2+}}(aq) + \ce{2 e-} \ce{<=>} \ce{Mn}(s)\) | \ (E_ {1/2}\) (voltios frente a SCE)” style="vertical-align:middle; ">—1.65 | 1 M NH 4 Cl más 1 M NH 3 |
| \(\ce{Ni^{2+}}(aq) + \ce{2 e-} \ce{<=>} \ce{Ni}(s)\) | \ (E_ {1/2}\) (voltios frente a SCE)” style="vertical-align:middle;” class="lt-chem-135882">
—0.70 —1.09 |
1 M KSCN 1 M NH 4 Cl más 1 M NH 3 |
| \(\ce{Zn^{2+}}(aq) + \ce{2 e-} \ce{<=>} \ce{Zn}(s)\) | \ (E_ {1/2}\) (voltios frente a SCE)” style="vertical-align:middle;” class="lt-chem-135882">
—0.995 —1.33 |
0,1 M KCl 1 M NH 4 Cl más 1 M NH 3 |