I diluted 100ml of 98% H2SO4 with 800ml of water. I then slowly added around 30g of CuSO4 and then found it difficult to breathe. I did this in a
closed area. I had no idea that SO2 gas would evolve from the addition of CuSO4. I opened the window but only after inhaling a significant amount of
the gas, which gave me a choking feeling and made me cough violently.
Should I be worried, and seek medical attention, or is this something that is harmless?symboom - 29-5-2011 at 13:47
your sulfuric acid what did you aquire it fromLanthanumK - 29-5-2011 at 15:25
You probably just made the H2SO4 hot from the hydrolysis, which made it release H2SO4 (or SO3) fumes, which accumulated in the closed room. I don't
think it has anything to do with the CuSO4. If you left a beaker of hot HCl sitting out in a closed area it would make your lungs unconfortable as
well upon entering the area.
Once, a closed container containing a small amount of a concentrated solution of HCl was opened by me. In about 3 seconds, I acidified my nasal
passages with a good dose of hydrogen chloride fumes.
From J.T. Baker msds: Inhalation [of sulfuric acid] produces damaging effects on the mucous membranes and upper respiratory tract. Symptoms may
include irritation of the nose and throat, and labored breathing. [deleted scary part]
[Edited on 29-5-2011 by LanthanumK]The WiZard is In - 29-5-2011 at 15:39
You did add the acid to the water!?!jonco - 29-5-2011 at 15:43
The beaker was hot to the touch while I was adding the acid a little at a time, but I didn't smell any noxious gas. It was only when I started added
the CuSO4. It could have been the hydrolysis, but 180g/L of H2SO4 is dilute enough that it won't burn you on contact, or release fumes. I'm not sure
what happened with this.hkparker - 29-5-2011 at 16:21
Purity of copper sulfate? H2SO4 sounds too dilute to make any acid fumes but if you had even a little sulfide in the copper sulfate you could have
produced some H2S.
I still think it was the heating of the H2SO4 releasing some H2SO4/SO3. Even if it seems like it was when you added CuSO4 because of a delay.
As The WiZard said, you added the acid to the water... right?Sedit - 29-5-2011 at 16:35
This is odd, I have been adding CuSO4 to H2SO4 of various concentration and have noted NO sort of fumes what so ever. I have been toying around with
that benzaldahyde synthesis and I have noticed no SO2 or SO3 fumes. There is something else going on here.jonco - 29-5-2011 at 18:03
I added the acid to the water, slowly so that it would not overheat. It did roil a bit, but no splatter. I added the 100ml I think in 6 small
quantities, waiting for the solution to cool down a bit after each one.
CuSO4 label says Min. Assy 99%.
I must say I found it a bit odd as well. I didn't expect gas evolution, as other people have done this before and no one mentioned doing it in a well
ventilated area.
I recall I did one other thing, but I don't know if that may be the cause of it. Before putting the lid on the H2SO4 bottle, I wiped off the excess
acid around the mouth of the bottle with tissue paper, which turned black. I rinsed the tissue paper with water before disposing of it.
[Edited on 30-5-2011 by jonco]woelen - 29-5-2011 at 22:33
I can only confirm what the others have said here. The only thing I can imagine is that either your acid or your H2SO4, or your container in which you
mixed the acid with water and to which you later added the CuSO4.
I have done similar things MANY times, and never had fumes which caused problems with breathing. H2SO4 at concentrations of a few tens of percent does
not fume, not in the cold and not when it is hot. Copper sulfate added to this also should have no effect at all.
Maybe there was some residue in the container, used for the mixing?
Did you notice a particular smell at some stage of the process?
[Edited on 30-5-11 by woelen]jonco - 30-5-2011 at 01:31
I feel normal today, so I guess there are no ill-effects from my strange experience yesterday.
The container was a PP beaker, which was washed with water before use.
The only time I noticed the smell was about half way into adding the CuSO4 to the H2SO4.
I stopped adding the CUSO4, trying to figure out what was going on, but the noxious, colorless gas had already started to fill the room, at which
point I found it diffcult to breathe, and left the room. When I can back about 5 mins later, the room was filled with some sort of gas, and I had to
vent the place.Bot0nist - 30-5-2011 at 04:19
I think maybe your attributing the 'gas' to the addition of the copper sulfate based on timing perhaps. No fumes should have been evolved during the
addition of your copper sulfate, I agree, but the culprit may have been dilution of the acid if it sputtered or more likely the 'burnt' towel.
Even though this was a pretty safe experiment I would recommend a little cross ventilation. Working in a stuffy room with no air exchange is not the
best idea, IMO.
Even a reaction of hydroxide solution and aluminum has aerosoled small droplets of lye that choked me up and stung my eyes.
I recently spilled 30 or so ml of 92% hot sulfuric acid onto a towel while prepping for a picric acid synthesis. As it reduced it to carbon a cloud of
acrid gas forced me to leave the room and dawn the respirator for clean up. I dilute all my strong acids in the hood now.
edit: Did you smell rotten eggs at any point? Can you describe in more detail how the fumes smelt.
[Edited on 30-5-2011 by Bot0nist]jonco - 30-5-2011 at 11:15
It had a smell like a rainy day, or ozone. It's hard to describe really. It just felt like there was no oxygen in the room, and it irritated my nasal
passage and throat, causing me to cough. It did seem heavier than air, since I felt it was more concentrated at the table level. I didn't get the
rotten egg smell.hissingnoise - 30-5-2011 at 11:31
Put a small pile of sulphur on a tiled floor, or whatever, ignite with a glowing cigarette end and bend down to smell.
When the SO<sub>2</sub> hits your nose, you'll straighten up so quick, your head'll swim!
And BTW, a lit fag-end won't ignite flammable vapours but the faint blue flame of burning sulphur will . . .
