# Why doesn't NaCl work for electrolysis? [closed]

So I found out online that to increase the conductivity of water for electrolysis, NaCl or NaOH is used.

However, upon using a low amount of NaCl in water and passing 12V through the solution, I noticed something weird, the cathode was bubbling a lot more than the anode (as expected in electrolysis - Hydrogen) but after 20 mins, there was no collection of gas on the anode. Why could this be?

When repeating the experiment with NaOH, the desired result was obtained with hydrogen and oxygen on the cathode and anode respectively.

• What was it that you expected, really? Oct 13 '21 at 14:00
• Important info is missing: Electrode materials! Oct 13 '21 at 14:01
• Steel could be reacting with chlorine. Did you see it corroded? Oct 13 '21 at 14:17
• Yes the anode was a bit corroded
– user117807
Oct 13 '21 at 14:28
• Oxygen? Why not chlorine? Oct 13 '21 at 14:34

At the cathode, $$\ce{H2O}$$ is decomposed according to $$\ce{2 H2O + 2 e- -> H2 + 2 OH-}$$ So some $$\ce{H2}$$ gas is produced, and the solution becomes basic. At the anode, two reactions occur simultaneously and independently : $$\ce{2 Cl- -> Cl2 + 2e-}$$ $$\ce{Fe -> Fe^{2+} + 2 e-}$$ So the anode is corroded. Now the chlorine $$\ce{Cl2}$$ produced by the first reaction is a gas relatively soluble in water, which reacts with the ions $$\ce{Fe^{2+}}$$ produced by the second reaction, according to :$$\ce{2 Fe^{2+} + Cl2 -> 2 Fe^{3+} + 2 Cl^-}$$ The ion $$\ce{Fe^{3+}}$$ is usually hydrated in aqueous solution taking a orange-brown color due to the ion $$\ce{[Fe(OH)]^{2+}}$$ produced by the reaction $$\ce{Fe^{3+} + 2 H2O -> [Fe(OH)]^{2+} + H3O^+}$$ And the solution becomes brownish and acidic around the anode