So I bought a bottle of CuSO4 root killer (nice blue crystals) and poured 3/4 of it out. I then replaced the missing CuSO4 crystals with Kosher Sea
Salt crystals dyed blue and then proceeded to shake vigorously for a few minutes. I left the container capped and closed for a month or so outside in
the cold (New england December weather).
Today i opened it to a massive wave of what smelled of chlorine gas. The blue salt was no longer dyed blue, some reverted back to clearish white while
many others were slightly green (think: sickly chlorine gas color green). The CuSO4 crystals seemed unchanged, still same blue color crystals.
So what happend? Was the dye an oxidizer? Was chlorine released and because of the cold the container didnt explode but instead the salt absorbed some
of the chlorine gas? Or is that not it at all?
Thanks
Sir_Gawain - 29-12-2023 at 12:44
Are you sure it’s chlorine? Hydrogen chloride seems more likely.Parakeet - 29-12-2023 at 13:35
I also wonder if it is really Cl2.
Can you test the gas with potassium iodide starch paper and pH strip?DraconicAcid - 29-12-2023 at 13:46
If the dye was an oxidizer, then your blue-dyed salt would have been giving off chlorine before you mixed it with copper sulphate.
What on earth were you trying to do by mixing the two salts?
Why would you use "kosher salt with blue dye in it" if you were trying to get a comprehensible reaction? If you use chemicals with unknown crap in
them, you will generally get unknown crap.
[Edited on 29-12-2023 by DraconicAcid]deadrush - 29-12-2023 at 17:04
I simply didnt want the wife to know id looted the CuSO4 lolSir_Gawain - 29-12-2023 at 17:28
Buy your own bottle!
Copper sulfate usually contains residual sulfuric acid. It reacts with the salt to form hydrochloric acid, which smells like chlorine. I don’t
think the dye has anything to do with it. deadrush - 29-12-2023 at 17:51
That is good to know and im fairly sure youre right. My only hesitation is the green color. Ive seen dense chlorine gas once (i made some in a sealed
container outside when it was 15F.) And id swear the color was almost identical. Also i was using 32% HCl that day like 30min earlier on something
else and i dont THINK it was the same. Im not the best with colors or specific smells though tbh.
Not a big deal, just thought it was interesting and was curious. Always looking for answers and to learn more!
I simply didnt want the wife to know id looted the CuSO4 lol
How ridiculous. Why don’t you buy her a new
bottle, and practice your recrystallization technique on the stuff you mucked up?bnull - 17-1-2024 at 18:06
It's just copper(II) chloride. The smell comes from the HCl released by the residual acid, as Sir_Gawain said. Take some of it and dissolve in water:
you'll see a beautiful green that turns blue if you add more water.
