Safe way to extract hydrogen from water through electrolysis

Question

I've done some research on google but most guides I've seen recommend adding salt to the mixture for better conductance which results in the release of chlorine.

Is there a way to perform electrolysis on water that releases hydrogen and at the same time does not release any gases that are harmful to humans? By that I mean can I use another electrolyte that does not produce harmful side effects (so sulfuric acid is also out, and I do realize it's next to impossible to do electrolysis on distilled water.)

I'm looking for a way to show this experiment to kids in enclosed space without good ventilation.

Welcome to chemistry.se! Please take a minute to go through the [tour] and maybe one more for the [help]. — Martin - マーチン, May 09 '15 at 10:27
@Martin I do realize you cannot perform destilation on destiled water. I'm looking for different electrolyte or other ideas on how to make the process safe (I know for example Sulfuric acid can be used as electrolyte to, but I don't really want to handle that either). — Marcin Raczkowski, May 09 '15 at 10:47
@martin thank you. The answer recommends 4 different salts. Could you tell me which one would be safest to handle? I'm reading about all of them on wiki now, but If you can put that in an answer I'd accept it and you'll get karma :) — Marcin Raczkowski, May 09 '15 at 10:59
Also, sodium hydrogen carbonate (baking soda) will work if dissolved in water. — sadljkfhalskdjfh, Mar 19 '16 at 08:56

score 3 · Accepted Answer · edited Apr 13 '17 at 12:57

Some sort of advice, since you are concerned with safety and demonstrating the experiment to children. You should generally not perform an experiment in a badly ventilated space. Please be aware, that the generated hydrogen gas is highly flammable and with the addition of the right amount of oxygen, it can make very loud booms: How explosive is hydrogen gas?

Here are two questions, that are very closely related and already contain the answer to your question:

In general any kind of salt as an electrolyte will do.

In low concentrations about 1-2 mol/L they are usually quite harmless. I personally would prefer diluted sulfuric acid. Any addition of group 2 salts may cause passivation of the electrodes by trapping carbon dioxide from the air.

Diluted sodium hydroxide or potassium hydroxide are also safe to handle.

Probably the safest is sodium sulfate, but it might not be the best performer.

Please wear safety goggles at all times during the experiment, best case: The children wear them, too.

Thank you very much! This is exactly what I was looking for and the more I read about Sodium Sulfate the better it looks. Safe to handle (I could show the crystals) and do not seem to produce any side effects. While I'll obviously open all windows etc. I don't have any way to ensure good ventilation outside of the fan. — Marcin Raczkowski, May 09 '15 at 11:30

Safe way to extract hydrogen from water through electrolysis

1 Answers1