35.8: Potenciales de reducción estándar y potenciales polarográficos de media onda
- Page ID
- 79081
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Potenciales de reducción estándar/formales
La siguiente tabla proporciona los valores de E o y E o ́ para reacciones de reducción seleccionadas. Los valores provienen de las siguientes fuentes (principalmente las dos primeras):
- Bard, A. J.; Parsons, B.; Jordon, J., eds. Potenciales estándar en soluciones acuosas, Dekker: New York, 1985
- Milazzo, G.; Caroli, S.; Sharma, V. K. Tablas de potenciales de electrodos estándar, Wiley: Londres, 1978;
- Swift, E. H.; Butler, E. A. Mediciones Cuantitativas y Equilibrios Químicos, Freeman: Nueva York, 1972.
- Bratsch, S. G. “Potenciales de Electrodo Estándar y Coeficientes de Temperatura en Agua a 298.15K, J. Phys. Chem. Ref. Datos, 1989, 18, 1—21.
- Latimer, W. M. Potenciales de oxidación, 2do. Ed., Prentice-Hall: Englewood Cliffs, Nueva Jersey, 1952
Se identifican sólidos, gases y líquidos; todas las demás especies son acuosas. Las reacciones de reducción en solución ácida se escriben usando H + en lugar de H 3 O +. Se puede reescribir una reacción reemplazando H + por H 3 O + y agregando al lado opuesto de la reacción una molécula de H 2 O por H +; así
H 3 ASo 4 + 2H + +2 e —\(\rightleftharpoons\) HASO 2 +2H 2 O
se convierte
H 3 ASo 4 + 2H 3 O + +2 e —\(\rightleftharpoons\) HASO 2 +4H 2 O
Las condiciones para los potenciales formales (E o ́) se listan junto al potencial.
Para la mayoría de las medias reacciones de reducción aquí reunidas, existen diferencias menores en los valores proporcionados por las referencias anteriores. En la mayoría de los casos, estas diferencias son pequeñas y no afectarán los cálculos. En algunos casos las diferencias no son insignificantes y el usuario puede encontrar discrepancias en los cálculos. Por ejemplo, Bard, Parsons y Jordon reportan un valor E o de —1.285 V para
\[\text{Zn(OH)}_4^{2-} + 2e^- \rightleftharpoons \text{Zn}(s) + 4\text{OH}^-\nonumber \]
mientras que Milazzo, Caroli y Sharma reportan el valor como —1.214 V, Swift reporta el valor como —1.22, Bratsch reporta el valor como —1.199 V y Latimer reporta el valor como —1.216 V.
| Aluminio | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Al}^{3+} + 3e^- \rightleftharpoons \text{Al}(s)\) | —1.676 | |
| \(\text{Al(OH)}_4^- + 3e^- \rightleftharpoons \text{Al}(s) + 4\text{OH}^-\) | —2.310 | |
| \(\text{AlF}_6^{3-} + 3e^- \rightleftharpoons \text{Al}(s) + 6\text{F}^-\) | —2.07 |
| Antimonio | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Sb} + 3\text{H}^+ + 3e^- \rightleftharpoons \text{SbH}_3(g)\) | —0.510 | |
| \(\text{Sb}_2\text{O}_5 + 6\text{H}^+ + 4e^- \rightleftharpoons 2\text{SbO}^+ + 3\text{H}_2\text{O}(l)\) | 0.605 | |
| \(\text{SbO}^+ + 2\text{H}^+ + 3e^- \rightleftharpoons \text{Sb}(s) + \text{H}_2\text{O}(l)\) | 0.212 |
| Arsénico | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{As}(s) + 3\text{H}^+ + 3e^- \rightleftharpoons \text{AsH}_3(g)\) | —0.225 | |
| \(\text{H}_3\text{AsO}_4 + 2\text{H}^+ + 2e^- \rightleftharpoons \text{HAsO}_2 + 2\text{H}_2\text{O}(l)\) | 0.560 | |
| \(\text{HAsO}_2 + 3\text{H}^+ + 3e^- \rightleftharpoons \text{As}(s) + 2\text{H}_2\text{O}(l)\) | 0.240 |
| Bario | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Ba}^{2+} + 2e^- \rightleftharpoons \text{Ba}(s)\) | —2.92 | |
| \(\text{BaO}(s) + 2\text{H}^+ + 2e^- \rightleftharpoons \text{Ba}(s) + \text{H}_2\text{O}(l)\) | —2.166 |
| Berilio | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Be}^{2+} + 2e^- \rightleftharpoons \text{Be}(s)\) | —1.99 |
| Bismuto | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Bi}^{3+} + 3e^- \rightleftharpoons \text{Bi}(s)\) | 0.317 | |
| \(\text{BiCl}_4^- + 3e^- \rightleftharpoons \text{Bi}(s) + 4\text{Cl}^-\) | 0.199 |
| Boro | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{B(OH)}_3 + 3\text{H}^+ + 3e^- \rightleftharpoons \text{B}(s) + 3\text{H}_2\text{O}(l)\) | —0.890 | |
| \(\text{B(OH)}_4^- + 3e^- \rightleftharpoons \text{B}(s) + 4\text{OH}^-\) | —1.811 |
| Bromo | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Br}_2(l) + 2e^- \rightleftharpoons 2\text{Br}^-\) | 1.087 | |
| \(\text{HOBr} + \text{H}^+ + 2e^- \rightleftharpoons \text{Br}^- + \text{H}_2\text{O}(l)\) | 1.341 | |
| \(\text{HOBr} + \text{H}^+ + e^- \rightleftharpoons \frac{1}{2} \text{Br}_2 + \text{H}_2\text{O}(l)\) | 1.604 | |
| \(\text{BrO}^- + \text{H}_2\text{O}(l) + 2e^- \rightleftharpoons \text{Br}^- + 2\text{OH}^-\) | 0.76 en NaOH 1 M | |
| \(\text{BrO}_3^- +6\text{H}^+ + 5e^- \rightleftharpoons \frac{1}{2} \text{Br}_2(l) + 3\text{H}_2\text{O}(l)\) | 1.5 | |
| \(\text{BrO}_3^- + 6\text{H}^+ +6e^- \rightleftharpoons \text{Br}^- + 3\text{H}_2\text{O}(l)\) | 1.478 |
| Cadmio | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Cd}^{2+} + 2e^- \rightleftharpoons \text{Cd}(s)\) | —0.4030 | |
| \(\text{Cd(CN)}_4^{2-} + 2e^- \rightleftharpoons \text{Cd}(s) + 4\text{CN}^-\) | —0.943 | |
| \(\text{Cd(NH}_3)_4^{2+} + 2e^- \rightleftharpoons \text{Cd}(s) + 4\text{NH}_3\) | —0.622 |
| Calcio | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Ca}^{2+} + 2e^- \rightleftharpoons \text{Ca}(s)\) | —2.84 |
| Carbono | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{CO}_2(g) + 2\text{H}^+ + 2e^- \rightleftharpoons \text{CO}(g) + \text{H}_2\text{O}(l)\) | —0.106 | |
| \(\text{CO}_2(g) + 2\text{H}^+ +2e^- \rightleftharpoons \text{HCO}_2\text{H}\) | —0.20 | |
| \(2\text{CO}_2(g) + 2\text{H}^+ +2e^- \rightleftharpoons \text{H}_2\text{C}_2\text{O}_4\) | —0.481 | |
| \(\text{HCHO} + 2\text{H}^+ + 2e^- \rightleftharpoons \text{CH}_3\text{OH}\) | 0.2323 |
| Cerio | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Ce}^{3+} + 3e^- \rightleftharpoons \text{Ce}(s)\) | —2.336 | |
| \(\text{Ce}^{4+} + e^- \rightleftharpoons \text{Ce}^{3+}\) | 1.72 |
1.70 en 1 M HClO 4 1.44 en 1 M H 2 SO 4 1.61 en 1 M HNO 3 1.28 en HCl 1 M |
| Cloro | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Cl}_2(g) + 2e^- \rightleftharpoons 2\text{Cl}^-\) | 1.396 | |
| \(\text{ClO}^- + \text{H}_2\text{O}(l) + e^- \rightleftharpoons \frac{1}{2} \text{Cl}_2(g) + 2\text{OH}^-\) | 0.421 en NaOH 1 M | |
| \(\text{ClO}^- + \text{H}_2\text{O}(l) + 2e^- \rightleftharpoons \text{Cl}^- + 2\text{OH}^-\) | 0.890 en NaOH 1 M | |
| \(\text{HClO}_2 + 2\text{H}^+ + 2e^- \rightleftharpoons \text{HOCl} + \text{H}_2\text{O}(l)\) | 1.64 |
| Cloro | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{ClO}_3^- + 2\text{H}^+ + e^- \rightleftharpoons \text{ClO}_2(g) + \text{H}_2\text{O}(l)\) | 1.175 | |
| \(\text{ClO}_3^- + 3\text{H}^+ + 2e^- \rightleftharpoons \text{HClO}_2 + \text{H}_2\text{O}(l)\) | 1.181 | |
| \(\text{ClO}_4^- + 2\text{H}^+ +2e^- \rightleftharpoons \text{ClO}_3^- + \text{H}_2\text{O}(l)\) | 1.201 |
| Cromo | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Cr}^{3+} + 3e^- \rightleftharpoons \text{Cr}(s)\) | —0.424 | |
| \(\text{Cr}^{2+} + 2e^- \rightleftharpoons \text{Cr}(s)\) | —0.90 | |
| \(\text{Cr}_2\text{O}_7^{2-} + 14\text{H}^+ + 6e^- \rightleftharpoons 2\text{Cr}^{3+} + 7\text{H}_2\text{O}(l)\) | 1.36 | |
| \(\text{CrO}_4^{2-} + 4\text{H}_2\text{O}(l) + 3e^- \rightleftharpoons \text{Cr(OH)}_4^- + 4\text{OH}^-\) | —0.13 en NaOH 1 M |
| Cobalto | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Co}^{2+} + 2e^- \rightleftharpoons \text{Co}(s)\) | —0.277 | |
| \(\text{Co}^{3+} + 3e^- \rightleftharpoons \text{Co}(s)\) | 1.92 | |
| \(\text{Co(NH}_3)_6^{3+} + e^- \rightleftharpoons \text{Co(NH}_3)_6^{2+}\) | 0.1 | |
| \(\text{Co(OH)}_3(s) + e^- \rightleftharpoons \text{Co(OH)}_2(s) + \text{OH}^-\) | 0.17 | |
| \(\text{Co(OH)}_2(s) + 2e^- \rightleftharpoons \text{Co}(s) + 2\text{OH}^-\) | —0.746 |
| Cobre | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Cu}^+ + e^- \rightleftharpoons \text{Cu}(s)\) | 0.520 | |
| \(\text{Cu}^{2+} + e^- \rightleftharpoons \text{Cu}^+\) | 0.159 | |
| \(\text{Cu}^{2+} + 2e^- \rightleftharpoons \text{Cu}(s)\) | 0.3419 | |
| \(\text{Cu}^{2+} + \text{I}^- + e^- \rightleftharpoons \text{CuI}(s)\) | 0.86 | |
| \(\text{Cu}^{2+} + \text{Cl}^- + e^- \rightleftharpoons \text{CuCl}(s)\) | 0.559 |
| Flúor | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{F}_2(g) + 2\text{H}^+ + 2e^- \rightleftharpoons 2\text{HF}(g)\) | 3.053 | |
| \(\text{F}_2(g) + 2e^- \rightleftharpoons 2\text{F}^-\) | 2.87 |
| Galio | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Ga}^{3+} + 3e^- \rightleftharpoons \text{Ga}(s)\) | —0.529 |
| Oro | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Au}^+ + e^- \rightleftharpoons \text{Au}(s)\) | 1.83 | |
| \(\text{Au}^{3+} + 2e^- \rightleftharpoons \text{Au}^+\) | 1.36 | |
| \(\text{Au}^{3+} + 3e^- \rightleftharpoons \text{Au}(s)\) | 1.52 | |
| \(\text{AuCl}_4^- + 3e^- \rightleftharpoons \text{Au}(s) + 4\text{Cl}^-\) | 1.002 |
| Hidrógeno | E (V) | E o ́ (V) |
|---|---|---|
| \(2\text{H}^+ + 2e^- \rightleftharpoons \text{H}_2 (g)\) | 0.00000 | |
| \(\text{H}_2\text{O}(l) + e^- \rightleftharpoons \frac{1}{2} \text{H}_2(g) + \text{OH}^-\) | —0.828 |
| Yodo | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{I}_2(s) + 2e^- \rightleftharpoons 2\text{I}^-\) | 0.5355 |
| Yodo | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{I}_3^- + 2e^- \rightleftharpoons 3\text{I}^-\) | 0.536 | |
| \(\text{HIO} + \text{H}^+ + 2e^- \rightleftharpoons \text{I}^- + \text{H}_2\text{O}(l)\) | 0.985 | |
| \(\text{IO}_3^- + 6\text{H}^+ + 5e^- \rightleftharpoons \frac{1}{2} \text{I}_2(s) + 3\text{H}_2\text{O}(l)\) | 1.195 | |
| \(\text{IO}_3^- + 3\text{H}_2\text{O}(l) + 6e^- \rightleftharpoons \text{I}^- +6\text{OH}^-\) | 0.257 |
| Hierro | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Fe}^{2+} + 2e^- \rightleftharpoons \text{Fe}(s)\) | —0.44 | |
| \(\text{Fe}^{3+} + 3e^- \rightleftharpoons \text{Fe}(s)\) | —0.037 | |
| \(\text{Fe}^{3+} + e^- \rightleftharpoons \text{Fe}^{2+}\) | 0.771 |
0.70 en HCl 1 M 0,767 en 1 M HClO 4 0,746 en 1 M HNO 3 0.68 en 1 M H 2 SO 4 0.44 in 0.3 M H 3 PO 4 |
| \(\text{Fe(CN)}_6^{3-} + e^- \rightleftharpoons \text{Fe(CN)}_6^{4-}\) | 0.356 | |
| \(\text{Fe(phen)}_3^{3+} + e^- \rightleftharpoons \text{Fe(phen)}_3^{2+}\) | 1.147 |
| Lantano | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{La}^{3+} + 3e^- \rightleftharpoons \text{La}(s)\) | —2.38 |
| Plomo | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Pb}^{2+} + 2e^- \rightleftharpoons \text{Pb}(s)\) | —0.126 | |
| \(\text{PbO}_2(s) + 4\text{H}^+ + 2e^- \rightleftharpoons \text{Pb}^{2+} + 2\text{H}_2\text{O}(l)\) | 1.46 | |
| \(\text{PbO}_2(s) + \text{SO}_4^{2-} + 4\text{H}^+ + 2e^- \rightleftharpoons \text{PbSO}_4(s) + 2\text{H}_2\text{O}(l)\) | 1.690 | |
| \(\text{PbSO}_4(s) + 2e^- \rightleftharpoons \text{Pb}(s) + \text{SO}_4^{2-}\) | —0.356 |
| Litio | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Li}^+ + e^- \rightleftharpoons \text{Li}(s)\) | —3.040 |
| Magnesio | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Mg}^{2+} + 2e^- \rightleftharpoons \text{Mg}(s)\) | —2.356 | |
| \(\text{Mg(OH)}_2(s) + 2e^- \rightleftharpoons \text{Mg}(s) + 2\text{OH}^-\) | —2.687 |
| Manganeso | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Mn}^{2+} + 2e^- \rightleftharpoons \text{Mn}(s)\) | —1.17 | |
| \(\text{Mn}^{3+} + e^- \rightleftharpoons \text{Mn}^{2+}\) | 1.5 | |
| \(\text{MnO}_2(s) + 4\text{H}^+ + 2e^- \rightleftharpoons \text{Mn}^{2+} + 2\text{H}_2\text{O}(l)\) | 1.23 | |
| \(\text{MnO}_4^- + 4\text{H}^+ +3e^- \rightleftharpoons \text{MnO}_2(s) + 2\text{H}_2\text{O}(l)\) | 1.70 | |
| \(\text{MnO}_4^- + 8\text{H}^+ + 5e^- \rightleftharpoons \text{Mn}^{2+} + 4\text{H}_2\text{O}(l)\) | 1.51 | |
| \(\text{MnO}_4^- + 2\text{H}_2\text{O}(l) + 3e^- \rightleftharpoons \text{MnO}_2(s) + 4\text{OH}^-\) | 0.60 |
| Mercurio | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Hg}^{2+} + 2e^- \rightleftharpoons \text{Hg}(l)\) | 0.8535 | |
| \(2\text{Hg}^{2+} +2e^- \rightleftharpoons \text{Hg}_2^{2+}\) | 0.911 |
| Mercurio | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Hg}_2^{2+} + 2e^- \rightleftharpoons 2\text{Hg}(l)\) | 0.7960 | |
| \(\text{Hg}_2\text{Cl}_2(s) + 2e^- \rightleftharpoons 2\text{Hg}(l) + 2\text{Cl}^-\) | 0.2682 | |
| \(\text{HgO}(s) + 2\text{H}^+ + 2e^- \rightleftharpoons \text{Hg}(l) + \text{H}_2\text{O}(l)\) | 0.926 | |
| \(\text{Hg}_2\text{Br}_2(s) + 2e^- \rightleftharpoons 2\text{Hg}(l) + 2\text{Br}^-\) | 1.392 | |
| \(\text{Hg}_2\text{I}_2(s) + 2e^- \rightleftharpoons 2\text{Hg}(l) + 2\text{I}^-\) | —0.0405 |
| Molibdeno | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Mo}^{3+} + 3e^- \rightleftharpoons \text{Mo}(s)\) | —0.2 | |
| \(\text{MoO}_2(s) + 4\text{H}^+ + 4e^- \rightleftharpoons \text{Mo}(s) + 2\text{H}_2\text{O}(l)\) | —0.152 | |
| \(\text{MoO}_4^{2-} + 4\text{H}_2\text{O}(l) + 6e^- \rightleftharpoons \text{Mo}(s) + 8\text{OH}^-\) | —0.913 |
| Níquel | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Ni}^{2+} + 2e^- \rightleftharpoons \text{Ni}(s)\) | —0.257 | |
| \(\text{Ni(OH)}_2(s) + 2e^- \rightleftharpoons \text{Ni}(s) + 2\text{OH}^-\) | —0.72 | |
| \(\text{Ni(NH}_3)_6^{2+} + 2e^- \rightleftharpoons \text{Ni}(s) + 6\text{NH}_3\) | —0.49 |
| Nitrógeno | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{N}_2(g) + 5\text{H}^+ + 4e^- \rightleftharpoons \text{N}_2\text{H}_5^+\) | —0.23 | |
| \(\text{N}_2\text{O}(g) + 2\text{H}^+ + 2e^- \rightleftharpoons \text{N}_2(g) + \text{H}_2\text{O}(l)\) | 1.77 | |
| \(2\text{NO}(g) + 2\text{H}^+ + 2e^- \rightleftharpoons \text{N}_2\text{O}(g) + \text{H}_2\text{O}(l)\) | 1.59 | |
| \(\text{HNO}_2 + \text{H}^+ + e^- \rightleftharpoons \text{NO}(g) + \text{H}_2\text{O}(l)\) | 0.996 | |
| \(2\text{HNO}_2 + 4\text{H}^+ + 4e^- \rightleftharpoons \text{N}_2\text{O}(g) + 3\text{H}_2\text{O}(l)\) | 1.297 | |
| \(\text{NO}_3^- + 3\text{H}^+ + 2e^- \rightleftharpoons \text{HNO}_2 + \text{H}_2\text{O}(l)\) | 0.94 |
| Oxígeno | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{O}_2(g) + 2\text{H}^+ + 2e^- \rightleftharpoons \text{H}_2\text{O}_2\) | 0.695 | |
| \(\text{O}_2(g) + 4\text{H}^+ + 4e^- \rightleftharpoons 2\text{H}_2\text{O}(l)\) | 1.229 | |
| \(\text{H}_2\text{O}_2 + 2\text{H}^+ + 2e^- \rightleftharpoons 2\text{H}_2\text{O}(l)\) | 1.763 | |
| \(\text{O}_2(g) + 2\text{H}_2\text{O}(l) + 4e^- \rightleftharpoons 4\text{OH}^-\) | 0.401 | |
| \(\text{O}_3(g) + 2\text{H}^+ + 2e^- \rightleftharpoons \text{O}_2(g) + \text{H}_2\text{O}(l)\) | 2.07 |
| Fosfóforo | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{P}(s, white) + 3\text{H}^+ + 3e^- \rightleftharpoons \text{PH}_3(g)\) | —0.063 | |
| \(\text{H}_3\text{PO}_3 + 2\text{H}^+ + 2e^- \rightleftharpoons \text{H}_3\text{PO}_2 + \text{H}_2\text{O}(l)\) | —0.499 | |
| \(\text{H}_3\text{PO}_4 + 2\text{H}^+ + 2e^- \rightleftharpoons \text{H}_3\text{PO}_3 + \text{H}_2\text{O}(l)\) | —0.276 |
| Platino | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Pt}^{2+} + 2e^- \rightleftharpoons \text{Pt}(s)\) | 1.188 | |
| \(\text{PtCl}_4^{2-} + 2e^- \rightleftharpoons \text{Pt}(s) + 4\text{Cl}^-\) | 0.758 |
| Potasio | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{K}^+ + e^- \rightleftharpoons \text{K}(s)\) | —2.924 |
| Rutenio | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Ru}^{3+} + 3e^- \rightleftharpoons \text{Ru}(s)\) | 0.249 | |
| \(\text{RuO}_2(s) + 4\text{H}^+ + 4e^- \rightleftharpoons \text{Ru}(s) + 2\text{H}_2\text{O}(l)\) | 0.68 | |
| \(\text{Ru(NH}_3)_6^{3+} + e^- \rightleftharpoons \text{Ru(NH}_3)_6^{2+}\) | 0.10 | |
| \(\text{Ru(CN)}_6^{3-} + e^- \rightleftharpoons \text{Ru(CN)}_6^{4-}\) | 0.86 |
| Selenio | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Se}(s) + 2e^- \rightleftharpoons \text{Se}^{2-}\) | —0.67 en NaOH 1 M | |
| \(\text{Se}(s) + 2\text{H}^+ + 2e^- \rightleftharpoons \text{H}_2\text{Se}(g)\) | —0.115 | |
| \(\text{H}_2\text{SeO}_3 + 4\text{H}^+ + 4e^- \rightleftharpoons \text{Se}(s) + 3\text{H}_2\text{O}(l)\) | 0.74 | |
| \(\text{SeO}_4^{3-} + 4\text{H}^+ + e^- \rightleftharpoons \text{H}_2\text{SeO}_3 + \text{H}_2\text{O}(l)\) | 1.151 |
| Silicio | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{SiF}_6^{2-} + 4e^- \rightleftharpoons \text{Si}(s) + 6\text{F}^-\) | —1.37 | |
| \(\text{SiO}_2(s) + 4\text{H}^+ + 4e^- \rightleftharpoons \text{Si}(s) + 2\text{H}_2\text{O}(l)\) | —0.909 | |
| \(\text{SiO}_2(s) + 8\text{H}^+ + 8e^- \rightleftharpoons \text{SiH}_4(g) + 2\text{H}_2\text{O}(l)\) | —0.516 |
| Plata | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Ag}^+ + e^- \rightleftharpoons \text{Ag}(s)\) | 0.7996 | |
| \(\text{AgBr}(s) + e^- \rightleftharpoons \text{Ag}(s) + \text{Br}^-\) | 0.071 | |
| \(\text{Ag}_2\text{C}_2\text{O}_4(s) + 2e^- \rightleftharpoons 2\text{Ag}(s) + \text{C}_2\text{O}_4^{2-}\) | 0.47 | |
| \(\text{AgCl}(s) + e^- \rightleftharpoons \text{Ag}(s) + \text{Cl}^-\) | 0.2223 | |
| \(\text{AgI}(s) + e^- \rightleftharpoons \text{Ag}(s) + \text{I}^-\) | —0.152 | |
| \(\text{Ag}_2\text{S}(s) + 2e^- \rightleftharpoons 2\text{Ag}(s) + \text{S}^{2-}\) | —0.71 | |
| \(\text{Ag(NH}_3)_2^+ + e^- \rightleftharpoons \text{Ag}(s) + 2\text{NH}_3\) | —0.373 |
| Sodio | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Na}^+ + e^- \rightleftharpoons \text{Na}(s)\) | —2.713 |
| Estroncio | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Sr}^{2+} + 2e^- \rightleftharpoons \text{Sr}(s)\) | —2.89 |
| Azufre | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{S}(s) + 2e^- \rightleftharpoons \text{S}^{2-}\) | —0.407 | |
| \(\text{S}(s) + 2\text{H}^+ + 2e^- \rightleftharpoons \text{H}_2\text{S}(g)\) | 0.144 | |
| \(\text{S}_2\text{O}_6^{2-} + 4\text{H}^+ + 2e^- \rightleftharpoons 2\text{H}_2\text{SO}_3\) | 0.569 | |
| \(\text{S}_2\text{O}_8^{2-} + 2e^- \rightleftharpoons 2\text{SO}_4^{2-}\) | 1.96 | |
| \(\text{S}_4\text{O}_6^{2-} + 2e^- \rightleftharpoons 2\text{S}_2\text{O}_3^{2-}\) | 0.080 | |
| \(2\text{SO}_3^{2-} + 2\text{H}_2\text{O}(l) + 2e^- \rightleftharpoons \text{S}_2\text{O}_4^{2-} + 4\text{OH}^-\) | —1.13 | |
| \(2\text{SO}_3^{2-} + 3\text{H}_2\text{O}(l) + 4e^- \rightleftharpoons \text{S}_2\text{O}_3^{2-} + 6\text{OH}^-\) | —0.576 en NaOH 1 M | |
| \(2\text{SO}_4^{2-} + 4\text{H}^+ + 2e^- \rightleftharpoons \text{S}_2\text{O}_6^{2-} + 2\text{H}_2\text{O}(l)\) | —0.25 | |
| \(\text{SO}_4^{2-} + \text{H}_2\text{O}(l) + 2e^- \rightleftharpoons \text{SO}_3^{2-} + 2\text{OH}^-\) | —0.936 | |
| \(\text{SO}_4^{2-} + 4\text{H}^+ + 2e^- \rightleftharpoons \text{H}_2\text{SO}_3 + \text{H}_2\text{O}(l)\) | 0.172 |
| Talio | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Tl}^{3+} + 2e^- \rightleftharpoons \text{Tl}^+\) |
1.25 en 1 M HClO 4 0.77 en HCl 1 M |
|
| \(\text{Tl}^{3+} + 3e^- \rightleftharpoons \text{Tl}(s)\) | 0.742 |
| Estaño | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Sn}^{2+} + 2e^- \rightleftharpoons \text{Sn}(s)\) | —0.19 en HCl 1 M | |
| \(\text{Sn}^{4+} + 2e^- \rightleftharpoons \text{Sn}^{2+}\) | 0.154 | 0.139 en HCl 1 M |
| Titanio | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Ti}^{2+} + 2e^- \rightleftharpoons \text{Ti}(s)\) | —0.163 | |
| \(\text{Ti}^{3+} + e^- \rightleftharpoons \text{Ti}^{2+}\) | —0.37 |
| Tungsteno | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{WO}_2(s) + 4\text{H}^+ + 4e^- \rightleftharpoons \text{W}(s) + 2\text{H}_2\text{O}(l)\) | —0.119 | |
| \(\text{WO}_3(s) + 6\text{H}^+ + 6e^- \rightleftharpoons \text{W}(s) + 3\text{H}_2\text{O}(l)\) | —0.090 |
| Uranio | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{U}^{3+} + 3e^- \rightleftharpoons \text{U}(s)\) | —1.66 | |
| \(\text{U}^{4+} + e^- \rightleftharpoons \text{U}^{3+}\) | —0.52 | |
| \(\text{UO}_2^+ + 4\text{H}^+ + e^- \rightleftharpoons \text{U}^{4+} + 2\text{H}_2\text{O}(l)\) | 0.27 | |
| \(\text{UO}_2^{2+} + e^- \rightleftharpoons \text{UO}_2^+\) | 0.16 | |
| \(\text{UO}_2^{2+} + 4\text{H}^+ + 2e^- \rightleftharpoons \text{U}^{4+} + 2\text{H}_2\text{O}(l)\) | 0.327 |
| Vanadio | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{V}^{2+} + 2e^- \rightleftharpoons \text{V}(s)\) | —1.13 | |
| \(\text{V}^{3+} + e^- \rightleftharpoons \text{V}^{2+}\) | —0.255 | |
| \(\text{VO}^{2+} + 2\text{H}^+ + e^- \rightleftharpoons \text{V}^{3+} + \text{H}_2\text{O}(l)\) | 0.337 | |
| \(\text{VO}_2^{+} + 2\text{H}^+ + e^- \rightleftharpoons \text{VO}^{2+} + \text{H}_2\text{O}(l)\) | 1.000 |
| Zinc | E (V) | E o ́ (V) |
|---|---|---|
| \(\text{Zn}^{2+} + 2e^- \rightleftharpoons \text{Zn}(s)\) | —0.7618 | |
| \(\text{Zn(OH)}_4^{2-} + 2e^- \rightleftharpoons \text{Zn}(s) + 4\text{OH}^-\) | —1.285 | |
| \(\text{Zn(NH}_3)_4^{2+} + 2e^- \rightleftharpoons \text{Zn}(s) + 4\text{NH}_3\) | —1.04 | |
| \(\text{Zn(CN)}_4^{2-} + 2e^- \rightleftharpoons \text{Zn}(s) + 4\text{CN}^-\) | —1.34 |
Potenciales Polarográficos de Media Onda
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 |
| \(\ce{Cr^{3+}}(aq) + \ce{3 e-} \ce{<=>} \ce{Cr}(s)\) | \ (E_ {1/2}\) (voltios frente a SCE)” style="vertical-align:middle;” class="lt-chem-362971">
—0.35\((+3 \ce{->} +2)\) —1.70\((+2 \ce{->} 0)\) |
1 M NH 4 Cl más 1 M NH 3 Tampón NH 4 +/ NH 3 1 M (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-362971">
—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-362971">
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-362971">
—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-362971">
—0.405 —0.435 |
1 M HNO 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-362971">
—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-362971">
—0.995 —1.33 |
0,1 M KCl 1 M NH 4 Cl más 1 M NH 3 |