[Pauline Solari (OP)]

Hi - I was looking at the electrical conductivity of solutions with my 11 year old the other day and I have some questions.

We were using Na Cl dissolved in distilled water and we had 2 copper electrodes. we passed a 12-volt current through.

I understand that at the anode we have 2Cl --> Cl2 (g) + 2e- and at the same time Cu(s) --> 2e- + Cu 2+ (aq) causing an oozing browish green stream from the electrode

I also understand that at the cathode we have 2H+ (aq) + 2e- -->H2 (g) and Cu2+(aq) + 2e- --> Cu (s)

What I don't understand though is what the brown (rust coloured) sediment is that we have in the dish after a period of time - ??copper chloride or ??copper oxide? or???.

Also, what happens to the Na+ ions and the OH- ions???

Can anyone explain this please and also how do both hydrogen and Cu2+ pick up e- from the cathode, but not the Na + and why chlorine gives off it's electrons at the anode and not OH-??

many thanks
Pauline

[Chemistry4me]

Can you imagine what would happen if Na⁺(aq) turned into Na(s)?  []

Something like this:

[Bored chemist]

The brown sludge is mainly Cu2O.