Source: did that as a teenager and did not die (trying to synthesize hydrogen as any normally constituted teenager would do), and the copper wires just ended up being entirely corroded until the immerged part disappeared. No hydrogen as I did not seal the apparatus properly. But I had a nice blueish precipitate instead. I absolutely had no idea it could have generated chlorine. I did sleep in the same room as the experiment for a full week. So I guess either my bedroom was well ventilated or it did not produce enough chlorine, or that it was just copper oxide.
My understanding is that usually the chlorine just reacts with the anode (cathode? I can never remember), unless you use an anode that it can't react with (graphite for instance).
Even if it did make chlorine, as long as your power wasn't too high it might not hurt you (much) due to ventilation. It is also very reactive, so it tends to get used up reacting with whatever random crap is near it.
Would that not be copper oxide?
Source: did that as a teenager and did not die (trying to synthesize hydrogen as any normally constituted teenager would do), and the copper wires just ended up being entirely corroded until the immerged part disappeared. No hydrogen as I did not seal the apparatus properly. But I had a nice blueish precipitate instead. I absolutely had no idea it could have generated chlorine. I did sleep in the same room as the experiment for a full week. So I guess either my bedroom was well ventilated or it did not produce enough chlorine, or that it was just copper oxide.