Yesterday I made a mixture of vinegar and salt and then electrolyzed it. I was just wondering if anyone could tell me what the process created, it would be greatly appreciated.

  • $\begingroup$ Vinegar in water is a slightly acidic solution. My guess would be evolution of hydrogen and oxygen gas at cathode and anode respectively. However, varying concentration and external potential might change the products $\endgroup$ – Amritansh Singhal Oct 27 '16 at 12:26
  • $\begingroup$ Would it create ethane? $\endgroup$ – WasabiPickle Nov 3 '16 at 9:10

As @Amritansh Singhal said, $\ce{H2}$ would be produced at the cathode from the electrolysis of both the water and some from the acetic acid (main ingredient of vinegar after water) and $\ce{O2}$ would accordingly be produced at the anode.

The question in your comment "Would it create ethane?" is where some more interesting chemistry might take place. The short answer is "very little at the most" since in the presence of water, the cell potential will be limited by the electrolysis of water as described above.

However, if you could obtain pure acetic acid and produce the proper cell potential, then you could see the Kolbe electrolysis reaction, which would produce ethane. According to excerpts from this Wikipedia article":

"The Kolbe reaction is formally a decarboxylative dimerisation of two carboxylic acids (or carboxylate ions)."

With respect to acetic acid specifically the above article states:

"The reaction mechanism involves a two-stage radical process: electrochemical decarboxylation gives a radical intermediate, then two such intermediates combine to form a covalent bond. As an example, electrolysis of acetic acid yields ethane and carbon dioxide:"
$$\ce{CH3COOH → CH3COO− → CH3COO· → CH3· + CO2}$$ followed by:
$$\ce{2CH3· → CH3CH3}$$

Where the latter product is ethane.

  • $\begingroup$ Well $\ce{CH3}\cdot$ is too reactive to survive for any length of time in aqueous solution. I'd guess that you'd only get ethane in very concentrated solutions of acetic acid (e.g glacial acetic acid). $\endgroup$ – MaxW Jan 27 '17 at 0:25
  • 1
    $\begingroup$ Yeah, it's going to react with most everything, though particularly another methyl radical. Reactions with radical intermediates will just tend to have lots of unwanted byproducts unless you have pure reagents, the right conditions, etc. That's part of the reason for my comment that you would get "very little at the most" unless you could get pure acetic acid, though I appreciate you mentioning that issue explicitly. $\endgroup$ – airhuff Jan 27 '17 at 1:02

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