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+ Electrolysis
+ Chemistry
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Michael Mombourquette

Green colored substances forming during electrolysis

David Charles Leithauser  Follow

@Bredget. If you don't know the nature of your electrodes, we cannot help you, because the greenish stuff is clearly coming from the electrodes, and not from the solution.Now if you electrolyze a salt solution, you will first produce some bubbles of $\ce{H2}$ and some ions $\ce{OH-}$ at the cathode (negative pole). Simultaneously, you will produce a mixture of oxagen $\ce{O2}$ plus chlorine bubbles $\ce{Cl2}$ at the anode (positive pole). But this chlorine is rather corrosive. It will soon attack and dissolve any metal at the electrode. And it may also react with the $\ce{OH-}$ ions coming from the cathode, and produce the reaction $\ce{Cl2 + 2 OH- ->ClO^- + Cl- + H2O}$. So the solution contains more and more $\ce{ClO-}$ ions, which are powerful oxidizing agents.

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E-Camelia  Follow
Thanks for your detailed answer, was really helpful. Do you suggest I use graphite as an anode?More
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Gary Karaff  Follow
Yes ! Graphite will not produce any corrosion like copper or iron. Graphite will not be chemically destroyed. But it may be victim of a physical corrosion. A graphite electrode will slowly be piulverized, with graphite powder falling down to the bottom of the solution. The best choice is platinum, which is not corroded at all.More
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