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I'm in need of hydrochloric acid for cleaning parts before electroplating, but I'd rather not deal with the HCl fumes given off by it, as I'd rather keep my workshop contents from rusting.

Given that HCl basically from what I've understood escapes any container it's put in, I had the idea of putting the container inside a bigger bucket and putting something in the bottom of the bucket to react with the fumes give off by the hydrochloric acid.

My first idea was either sodium bicarbonate or lye in solid form, would these react with it or do I need to have the base in liquid form? I'd rather not have my hydrochloric acid container covered in a lye solution.

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  • $\begingroup$ Marble or limestone scraps likely would serve as well, and you could even make a retaining wall with polyethylene netting, so that the cleaning bucket would be well below the level of surrounding limestone chips. Also, keep the opening just large enough tpo admit the parts. Definitely don't use lye, which is perhaps more dangerous than HCL, as well as hygroscopic! $\endgroup$ Mar 22, 2021 at 0:05

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Inexpensive [about US\$0.30 / liter] marble or limestone scraps, $\ce{CaCO3}$, likely would serve well. You could make an outer bucket with polyethylene netting, so that the pickling bucket would be well below the level of surrounding limestone chips. Coarse netting would not work with powders. Make the neck just large enough to admit the parts.

Better would would be to draw air continuously from above the container through a scrubber stack filled with marble or limestone chips, and possibly vent outside.

Definitely don't use lye, $\ce{NaOH}$, which is perhaps more dangerous than $\ce{HCL}$, as well as hygroscopic! You'd wind up with a puddle of caustic lye solution at the bottom of the outer bucket. And $\ce{NaHCO3}$ would also make a mess, though non-toxic.

BTW, if using large amounts, be careful that a spill into the outer container doesn't release so much $\ce{CO2}$ as to displace air and asphyxiate someone.

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  • $\begingroup$ We're talking maybe 5 liters here of HCl at 30ish % at the most. My idea would be to seal both containers, and just make the outer bucket say 20 liters or so. I'll have to think about a scrubber stack instead, that way I could theoretically at least make a water trap with some suitable solution in it. $\endgroup$
    – Stuggi
    Mar 22, 2021 at 1:36

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