Timeline for In a voltaic cell with standard hydrogen electrode is the measure half cell always the cathode?
Current License: CC BY-SA 4.0
11 events
| when toggle format | what | by | license | comment | |
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| May 6, 2023 at 19:31 | vote | accept | Physics | ||
| Apr 21, 2023 at 16:41 | answer | added | jimchmst | timeline score: 0 | |
| Apr 21, 2023 at 8:47 | history | edited | Poutnik | CC BY-SA 4.0 |
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| Apr 21, 2023 at 7:25 | comment | added | Poutnik | See results of the search site:chemistry.stackexchange.com cathode potential cell negative galvanic OR voltaic and generally also the Related section on the right side of the CH SE content page. | |
| Apr 21, 2023 at 7:16 | comment | added | Poutnik | The half cell reduction potential can be seen as the relative external potential (wrt SHE), that has to be set on the considered half cell to keep the half-cell at the edge between being a cathode and being an anode. The halfcell is an anode if Eext > E and vice versa. This addresses just TD, but not kinetic aspects. Many potentials are due frozen kinetics purely formal. | |
| Apr 21, 2023 at 5:52 | comment | added | Physics | So whether if an electrode is a cathode or anode it will always be a "formal" cathode. However, when you calculate the E° the value would either be neg or positive. If its an actual "anode" the electrode would be having electrons flowing out from that end and the cell will have a negative E°? | |
| Apr 21, 2023 at 5:48 | comment | added | Poutnik | It is formal cathode, but actually anode, as the Gibbs energy change and related potential are formally evaluated in this case in the direction opposite to spontaneity. If we used absolute values of reduction potentials instead, it would bring huge mess. | |
| Apr 21, 2023 at 5:46 | comment | added | Physics | Sorry I am not quite understanding. So its the cathode even though it had less "electron wanting desire" because hydrogen is the lowest? | |
| Apr 21, 2023 at 5:43 | comment | added | Poutnik | Formal negative reduction potential (Positive reaction Gibbs energy as $\Delta G^{\circ}_r = -nFE^{\circ}$) for being cathode means positive oxidation potential (negative reaction Gibbs energy) for being actually anode, as the latter is the direction of spontaneity. Reaction H2 + 2 Na+ -> 2 H+ + 2 Na has highly positive reaction Gibbs energy and highly negative formal reduction potential. | |
| S Apr 21, 2023 at 5:26 | review | First questions | |||
| Apr 21, 2023 at 14:08 | |||||
| S Apr 21, 2023 at 5:26 | history | asked | Physics | CC BY-SA 4.0 |