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What reactions will occur at the anodes and electrodes of two iron electrolytic cells: both with iron metal electrodes, one with an iron(II) sulphate electrolyte, the other with an iron(III) sulphate electrolyte?

I set up an experiment with both types of cells connected in series, which yielded the following qualitative data:

  • Both cathodes saw vigorous bubbling--to me implying hydrogen gas evolution.
  • Also, there appeared to be a darkish iron plating on the cathode, implying two reactions occurring here.
  • Some bubbling at anodes.
  • Large quantity of dark green precipitate formed in Iron(II) electrolyte, I would assume $\ce{Fe(H2O)4(OH)2}$ precipitate.
  • A deepening orange in iron(III) solution and a relatively small quantity of orange precipitate, I would assume $\ce{Fe(H2O)3(OH)3}$ precipitate.
  • pH of electrolytes remained constant (measured with a pH probe). Conductivity of iron(III) solution remained constant, whilst conductivity of iron(II) solution--which was almost 20 times higher--steadily fell.

It seems to me that similar things are happening at the respective cathodes of the iron(II) and iron(III) cells: both hydrogen gas and iron metal are evolving. The hydrogen gas evolution momentarily increases pH, pushing equilibrium of iron complexes towards the precipitates--thus keeping pH constant.

I'm less sure about the anodes. But I think iron is entering solution as Fe(II) and Fe(III), respectively, with some oxygen evolution.

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