Difference between revisions of "Reference Electrode Potentials"

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! scope="col" | Reference
 
! scope="col" | Reference
 
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! scope="row" | Hg/Hg<sub>2</sub >Cl<sub>2</sub>, KCl (0.1 M) || 0.3337 || 0.0925 || - || 1,3   
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! scope="row" | Hg/Hg<sub>2</sub >Cl<sub>2</sub>, KCl (0.1 M) || 0.3337 || 0.0925 || - || 1, 3   
 
|-
 
|-
 
! scope="row" | Hg/Hg<sub>2</sub >Cl<sub>2</sub>, KCl (0.1 M) || 0.336 || 0.092 || Yes || 2
 
! scope="row" | Hg/Hg<sub>2</sub >Cl<sub>2</sub>, KCl (0.1 M) || 0.336 || 0.092 || Yes || 2
 
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! scope="row" | NCE || 0.2801 || 0.0389 || - || 1,3
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! scope="row" | NCE || 0.2801 || 0.0389 || - || 1, 3
 
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! scope="row" | NCE || 0.283 || 0.039 || Yes || 2
 
! scope="row" | NCE || 0.283 || 0.039 || Yes || 2
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! scope="row" | Hg/Hg<sub>2</sub >Cl<sub>2</sub>, KCl (3. 5M) || 0.250 || 0.006 || Yes || 2
 
! scope="row" | Hg/Hg<sub>2</sub >Cl<sub>2</sub>, KCl (3. 5M) || 0.250 || 0.006 || Yes || 2
 
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|-
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! scope="row" | SCE || 0.2412 || 0 || - || 1,3
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! scope="row" | SCE || 0.2412 || 0 || - || 1, 3
 
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! scope="row" | SCE || 0.244 || 0 || Yes || 2
 
! scope="row" | SCE || 0.244 || 0 || Yes || 2
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'''References'''
 
'''References'''
  
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(1) "Electrochemical Methods: Fundamentals and Applications", AJ Bard and LR Faulkner, John Wiley & Sons, NY (2000). See the table on inside back cover.
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1. "Electrochemical Methods: Fundamentals and Applications", AJ Bard and LR Faulkner, John Wiley & Sons, NY (2000). See the table on inside back cover.
  
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(2) "Electrochemistry for Chemists, Second Edition", DT Sawyer, AJ Sobkowiak, J Roberts, Jr., John Wiley & Sons, NY (1995). See Section 5.2.
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2. "Electrochemistry for Chemists, Second Edition", DT Sawyer, AJ Sobkowiak, J Roberts, Jr., John Wiley & Sons, NY (1995). See Section 5.2.
  
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(3) "Handbook of Analytical Chemistry", L Meites (ed.), McGraw Hill, NY (1963). See Section 5.
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3. "Handbook of Analytical Chemistry", L Meites (ed.), McGraw Hill, NY (1963). See Section 5.
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<ref>{{cite book|last=Andrews|first=Donald H.|author2=Richard J. Kokes|title=Fundamental Chemistry|publisher=John Wiley & Sons, Inc.|location=New York|year=1962|page=482|chapter=Electrochemistry}}</ref>
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==References==
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{{Reflist}}
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Revision as of 13:37, 4 August 2014

The Calomel Electrode

The calomel electrode is usually constructed from a platinum wire inserted into a mixture of calomel (mercurous chloride, Hg2Cl2) and liquid mercury, with an electrolyte solution of KCl or NaCl. The relevant half cell equation is: Hg2Cl2 + 2e– → 2Hgliq + 2Cl–

As this equation implies the electrode potential is dependent on chloride concentration, but independent of hydrogen ion (acid) concentration.


Table 1. Potential (V) of the Calomel Electrode at 25°C
Conditions vs NHE vs SCE LJ Reference
Hg/Hg2Cl2, KCl (0.1 M) 0.3337 0.0925 - 1, 3
Hg/Hg2Cl2, KCl (0.1 M) 0.336 0.092 Yes 2
NCE 0.2801 0.0389 - 1, 3
NCE 0.283 0.039 Yes 2
Hg/Hg2Cl2, KCl (3. 5M) 0.250 0.006 Yes 2
SCE 0.2412 0 - 1, 3
SCE 0.244 0 Yes 2
SSCE 0.2360 -0.0052 - 1

Notes

LJ, liquid junction. Value obtained using a cell which included a liquid junction potential.
NCE, normal calomel electrode: Hg/Hg2Cl2, KCl (1 M)
NHE, normal hydrogen electrode
SCE, saturated calomel electrode: Hg/Hg2Cl2, KCl (sat'd)
SSCE, saturated salt calomel electrode: Hg/Hg2Cl2, NaCl (sat'd)


References

1. "Electrochemical Methods: Fundamentals and Applications", AJ Bard and 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 Section 5.

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