I am planning to electrolyze water for an experiment. However, I have limited resources and want to do it as safely as possible

The resources that I have:

  • $\pu{12 V}$ DC battery
  • Graphite (in the form of a pencil lead)
  • Stainless Steel
  • Alligator lead clips
  • Sodium Hydroxide ($\ce{NaOH}$)
  • Sodium Sulfate ($\ce{Na2SO4}$)

In such a condition, what would be the best electrode and electrolyte for this experiment?

  • $\begingroup$ What kind of battery and pencil leads? A 12V car battery might burn through your skinny 0.5-0.7mm pencil leads (your "graphite electrodes") rather quickly if your salt solution is conductive enough and/or if the leads are sufficiently close to each other. Not to mention that $\ce{2H2O(\ell) \to 2H2(g) + O2(g)}$ doesn't require that much overpotential anyway... $\endgroup$ – ManRow Apr 10 at 8:41
  • $\begingroup$ 12V source would cause a violent rate of electrolysis, if the source is hard, or the source can be damaged, if it is a soft voltage source without protection. Eventually both. Unless other measures are applied, consider serial resistor $R[\Omega] \approx \frac{10 [V]}{I [A]}$, where I is intended current, safe for both electrolysis and the power source. $\endgroup$ – Poutnik Apr 10 at 15:03

Both sodium hydroxide and sulfate will yield same gases on the electrodes but sulfate solution will be neutral $\mathrm{p}H$ so you would want to stick with that. For the electrodes safest option is pure graphite because stainless steel anode will probably produce hexavalent chromium which is not very good.


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