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Electrolysis of baking soda solution?

  1. Oct 19, 2013 #1
    What is being produced in electrolysis of water with baking soda (NaHCO3) dissolved in it, and carbon electrodes?
    Seems to be an extremely simple question, but every place i google up have a different answer.

    In practice, there is hydrogen on the cathode - it burns - but on the anode i get some unknown gas.
    It does not smell of anything - neither the itchy smell of CO2, nor fresh smell of oxygen, and i can't seem to get any reaction from a lit match.

    So, what is happening in there?
    Second question - what is happening in the water?
    One place i read that it would slowly turn into NaOH solution - would that actually happen?
  2. jcsd
  3. Oct 23, 2013 #2


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    Staff: Mentor

    CO2/O2 mixture perhaps? When oxygen is produced (which is almost for sure the main reaction) it can oxidize carbon electrodes, plus, one the products of the electrolysis are H+ - depending on the concentrations they can acidify solution in the vicinity of the electrode enough to decompose the carbonate.

    But I am just guessing. Note that there is probably no one answer to the question - what is really happening can depend on the concentration, applied voltage, properties of the electrode surfaces, mixing and partial pressure of CO2 in the air above the solution. By no means this is a simple system.
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