Chemical Forums
Chemistry Forums for Students => Physical Chemistry Forum => Topic started by: Zensation on January 30, 2014, 03:27:31 AM
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In such a situation, in the catholyte, what happens to the hydroxide ions?
Say you were doing electrolysis on water to collect H2 only from the divided cell. Water would be split at the cathode :
2 H2O(l) + 2eā ā H2(g) + 2 OH-(aq)
On wikipedia it says the OH-anions would gravitate to the anode to merge with the H+ cations that are formed... but what if they can't get over there.
Do the OH- anions just continually build up in the cell? Are these unstable in their current forms, and likely to react? For some reason I imagine O2 and H2 to be formed if two of these react, but I have an inkling that is not correct, as there is no mention of it anywhere.
I have seen in situations of electrocatalytic reductions in a divided cell that the organic material is extracted out and then acidified to a salt form, and many of these papers make no mention of how the hydroxide anions would act as a base and neutralize any acid before any acid can react with the organic molecule. Which would imply that the Hydroxide anions are not existing at that stage of the extraction. What happens to them?
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If you can somehow stop transfer of the ions, a counterpotential will build up pretty soon and the electrolysis will stop.
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When you say stop the transfer of ions... are you implying that hydroxide anions will travel through the salt-bridge of the divided cell? I'm honestly asking because I have no clue. Is this possible? I thought a salt-bridge would merely act to transfer the electrons.
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Salt bridge doesn't transfer electrons - it transfers charge allowing ions to move.