What happens when salt water is electrolyzed with a copper anode and a copper cathode? [closed]








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I heard that copper oxide is formed on the cathode and copper chloride is formed on the anode, is this correct?
I don't have much knowledge of chemistry, so I can't find out much by searching on Google.




The chemistry here can be explained from the associated products of the electrolysis of brine. To quote an [education source](https://chem.libretexts.org/Bookshelves/General_Chemistry/Book%3A_ChemPRIME_(Moore_et_al.)/17%3A_Electrochemical_Cells/17.03%3A_Electrolysis_of_Brine):



> 
> Three important chemicals, NaOH, Cl2, H2, can be obtained by electrolyzing an aqueous NaCl solution (brine). This forms the basis of the chlor-alkali industry. The diaphragm cell (also called a Hooker cell)...
> 
> 
> 


As such, depending on the cell design, expect also hypochlorous acid:


$\ce{Cl2 (g) + H2O (l) <-> HCl (aq) + HOCl(aq) }$


and hypochlorite with OH- as a side product of the electrolysis of the brine:


$\ce{ OH- + HOCl -> H2O + ClO-}$


However, some of the $\ce{HOCl}$ can also engage in a Fenton-type reaction ([example here](https://www.researchgate.net/publication/275818872_Influence_of_Chelating_Agents_on_Fenton-Type_Reaction_Using_Ferrous_Ion_and_Hypochlorous_Acid/link/5780e3c308ae69ab88262a03/download)) with $\ce{Cu}$ (and, to a lesser extent, $\ce{HOCl}$ acting on $\ce{Cu2O}$ resulting in some possible $\ce{CuO}$ or even a basic chloride formation) generally depicted as follows:


$\ce{Cu/Cu+ + HOCl -> Cu+/Cu++ + .OHCl-}$


where the latter radical intermediate can further break down with products dependent on the pH level (here, likely over pH 7 from $\ce{OH-}$ created in the parallel electrolysis reaction) and the chloride concentration. Source: See reactions listed in Supplement Table S1 [available here](http://www.mdpi.com/1420-3049/22/10/1684) by clicking on *Supplement File* to obtain a download.


Support: With metal spoons serving as electrodes for the electrolysis of a saltwater solution, there is clear discoloration of one of the spoon electrodes (visible at 5 minutes and 20 seconds into this [science experiment video](https://www.youtube.com/watch?v=T-OwWOYHhMI)).


Bottomline in time, expect similar discoloration of a copper electrode as well from the associated electrolysis products.


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