I plan to do the electrolysis of dilute sulphuric acid. This will produce hydrogen gas and oxygen gas at the anodes. I do not plan to collect these gases, but to simply let it form and release into the air without separating them. Would this carry any risk whatsoever, considering that an electric setup is nearby?

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    $\begingroup$ How many anodes does your system have ;-) Seriously though, your cell will have an anode and a cathode. I'll let you look up which gas is produced at which electrode. As far as there being "any risk whatsoever" of an explosion we'd have to say yes, though it is small and depends on the construction of your apparatus. $\endgroup$ – airhuff Jul 13 '19 at 5:34
  • $\begingroup$ Can you provide some more detail about the power source you'll use? Unless you're using a lot of power, you're unlikely to reach explosive levels of hydrogen in air. $\endgroup$ – jeffB Jul 13 '19 at 13:49

For hydrogen to burn or explode in air, its concentration needs to be at least 4%.

Unless you're using very high power levels, you're unlikely to reach that concentration in the room's air. You could ignite bubbles of hydrogen as soon as they pop at the surface, but if you don't, the hydrogen (with about 1/8 the density of air) will rise quickly, diffusing into the air as it goes.

If you're doing this using a battery, or a small line-operated power supply, there's very little danger of explosion.

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  • $\begingroup$ I'll be using a maximum of 6V from a power supply and I plan to use a 2M solution of sulfuric acid for no more than 10 mins at a time. I suppose this would not create enough Hydrogen to potentially become dangerous. $\endgroup$ – TheTenthBox Jul 14 '19 at 6:16
  • $\begingroup$ It's not the voltage that's important, but the current. How much current can the power supply provide? Unless it's in the tens of amps, you'll be fine -- and if it is in the tens of amps, you'll have more trouble from boiling your electrolyte due to excess power. At one amp, you'd be producing a few cc's of hydrogen per minute, far too little to pose any serious risk. $\endgroup$ – jeffB Jul 14 '19 at 18:20

I asked a somewhat similar question a few weeks ago and Poutnik made a smart suggestion that I simply mix the H2 with nitrogen to keep it safely below explosive concentrations, which I set out to do prior to extracting it outside with a fan. So the nitrogen ensure that concentrations are low enough for the fan engine's sparks not to light it on, and the fan extraction avoids both hydrogen and nitrogen accumulation in the building.

You can buy the fans and tubing in stores made for hydroponic gardening. The tubing looks like this:

enter image description here

Also keep in mind that every time you turn an electric switch on or off, a voltage peak occurs which ionises a small amount of air between the contacts and creates a tiny spark, so an electric setup nearby that is turned on / off may be hard to separate from having a "spark", which may be as dangerous as any other sparks if the gaseous mix penetrates the switch area.


How can I neutralise H2 gas without burning it?

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