# What Type of Gas Would Vinegar and Epsom Salt Create Under Electrolysis?

I'm restoring a motorcycle and have a small homemade DIY zinc plating operation which consists of vinegar, epsom salt, a piece of zinc and a power supply.

When I plate a steel piece such as a bolt or small hardware piece, the piece in the solution starts forming small bubbles and it appears to be "gassing off" something. I was wondering what type of gas this may be and if it's harmful to breathe.

• Vinegar and Epsom salt would not create anything. Vinegar and zinc, though, would create hydrogen. No, it will not poison you. – Ivan Neretin Nov 24 '16 at 13:50
• You're creating hydrogen gas at your part. No toxicity hazard. You need a substantial zinc concentration in the solution before you'll plate much metal -- are you sure you're actually putting zinc down? When I get a chance, I'll try to post a more thorough answer (unless I get beaten to the punch...). – hBy2Py Nov 24 '16 at 13:51
• Thank you both for answering my question. @hBy2Py Yea, I'm laying zinc down nicely on the parts. It just has a hard time getting into concave areas such as inside a nut or irregular shaped hardware piece – Stuart Nov 24 '16 at 14:00
• Yep, throwing into the insides of features is a common plating challenge. – hBy2Py Nov 24 '16 at 14:07

You're most likely forming $\ce{H2}$ gas at the part.
If you're plating anywhere above about $2~\mathrm V$, that is probably sufficient overpotential to cause part of the passed current to go toward electrolysis of water.