Difference between revisions of "Reference Electrode Potentials"
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The calomel electrode is usually constructed from a platinum wire inserted into a mixture of calomel (mercurous chloride, Hg<sub>2</sub >Cl<sub>2</sub>) and mercury with an electrolyte solution of KCl or NaCl. The relevant half equation is: | The calomel electrode is usually constructed from a platinum wire inserted into a mixture of calomel (mercurous chloride, Hg<sub>2</sub >Cl<sub>2</sub>) and mercury with an electrolyte solution of KCl or NaCl. The relevant half equation is: | ||
− | |||
Hg<sub>2</sub >Cl<sub>2</sub> + 2e<sup>–</sup> == 2Hg<sub>liq</sub> + 2Cl<sup>–</sup> | Hg<sub>2</sub >Cl<sub>2</sub> + 2e<sup>–</sup> == 2Hg<sub>liq</sub> + 2Cl<sup>–</sup> | ||
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:NHE, normal hydrogen electrode | :NHE, normal hydrogen electrode | ||
− | + | (1) "Electrochemical Methods: Fundamentals and Applications", AJ Bard & LR Faulkner, John Wiley & Sons, NY (2000). See the table on inside back cover. | |
+ | |||
(2) "Electrochemistry for Chemists, Second Edition", DT Sawyer, AJ Sobkowiak, J Roberts, Jr., John Wiley & Sons, NY (1995). See Section 5.2. | (2) "Electrochemistry for Chemists, Second Edition", DT Sawyer, AJ Sobkowiak, J Roberts, Jr., John Wiley & Sons, NY (1995). See Section 5.2. | ||
+ | |||
(3) "Handbook of Analytical Chemistry", L Meites, ed., McGraw Hill, NY (1963). See Sect 5. | (3) "Handbook of Analytical Chemistry", L Meites, ed., McGraw Hill, NY (1963). See Sect 5. |
Revision as of 12:55, 4 August 2014
The calomel electrode is usually constructed from a platinum wire inserted into a mixture of calomel (mercurous chloride, Hg2Cl2) and mercury with an electrolyte solution of KCl or NaCl. The relevant half equation is: Hg2Cl2 + 2e– == 2Hgliq + 2Cl–
Conditions | vs NHE | vs SCE | LJ | Reference |
---|---|---|---|---|
Hg/Hg2Cl2, KCl (0.1M) | 0.3337 | 0.0925 | - | 1,3 |
Hg/Hg2Cl2, KCl (0.1M) | 0.336 | 0.092 | Yes | 2 |
Hg/Hg2Cl2, KCl (1M) NCE (Normal Calomel) | 0.2801 | 0.0389 | - | 1,3 |
Hg/Hg2Cl2, KCl (1M) NCE (Normal Calomel) | 0.283 | 0.039 | Yes | 2 |
Hg/Hg2Cl2, KCl (3.5M) | 0.250 | 0.006 | Yes | 2 |
Hg/Hg2Cl2, KCl (sat'd) SCE (Sat'd Calomel) | 0.2412 | 0 | - | 1,3 |
Hg/Hg2Cl2, KCl (sat'd) SCE (Sat'd Calomel) | 0.244 | 0 | Yes | 2 |
Hg/Hg2Cl2, NaCl (sat'd) | 0.2360 | -0.0052 | - | 1 |
NOTES
- SCE, saturated calomel electrode
- SSCE, saturaded salt calomel electrode
- NCE, normal calomel electrode
- NHE, normal hydrogen electrode
(1) "Electrochemical Methods: Fundamentals and Applications", AJ Bard & LR Faulkner, John Wiley & Sons, NY (2000). See the table on inside back cover.
(2) "Electrochemistry for Chemists, Second Edition", DT Sawyer, AJ Sobkowiak, J Roberts, Jr., John Wiley & Sons, NY (1995). See Section 5.2.
(3) "Handbook of Analytical Chemistry", L Meites, ed., McGraw Hill, NY (1963). See Sect 5.