DalisAndy
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Sulfur dioxide testing
Would using a potassium permanganate soaked stop of paper work as a testing strip for sulfur dioxide. Or is their a less toxic and dangerous way to
test for sulfur dioxide. I know potassium dichromate is usually use for that, but I would prefer to use something less carcinogenic
Elements Collected: 19/81 (Excluding all radioactive, using placecard for those)
Any tips or good sources are welcome.
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Upsilon
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If you're just trying to see if it's present, it has a pretty distinct smell. You'll smell it long before it presents a health hazard. That doesn't
mean to just whiff a flask that's full of it though.
If you don't want to do that, then you could also bubble the gas through sodium hydroxide solution. This will make sodium sulfite which will react
with acids to make sulfur dioxide again (the bubbling of which indicates the reaction went as theorized, thus proving you had sulfur dioxide to begin
with).
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SunriseSunset
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Be very careful... this one time I tried cleaning residue from a flask with concentrated sulfuric acid and it started to smoke black smoke by surprise
and i got a decent wiff pretty close to the top of the flask, and about a minute later my lungs started weezing pretty bad. I was extremely scared to
say the least and was considering on going to the E.R. I tried to calm myself and found online that it was most likely sulfur dioxide due to the color
of the "smoke" n putting a link to the symptoms of exposure. Luckily though, after about 35 minutes it started to get better slowly and after about a
hour or two I felt a lot better. It felt like my lungs were starting to stick together. Not a fun feeling at all!
[Edited on 16-10-2015 by SunriseSunset]
Why do chemists call helium, curium and barium the medical elements?
because if you cant helium or curium, you barium! - Heimerdinger
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woelen
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A fairly safe test for SO2 is using paper soaked with acidified KMnO4-solution. Dissolve a small amount of KMnO4 in 3...5% H2SO4. You get a dark
purple solution. Soak the paper with this and keep close to the flow of gas which is tested for SO2. If the gas is present the color of the KMnO4
fades. No need to fear dangerous reactions.
Do not store the test strips, prepare immediately before use. This is because KMnO4 quickly deteriorates when in contact with paper.
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I do not understand Sunrise's post in this context. Your black cloud of smoke definitely is not SO2. It most likely is carbon/charred material. Of
course, the smoke might have contained some SO2 as well.
SO2 is a colorless very pungent gas of moderate toxicity. You certainly should not deeply breathe a large amount of this gas. That will be extremely
unpleasant. However, the gas has good warning properties. Before its concentration becomes really dangerous, its presence will be untolerable and you
automatically will flee from the place.
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chornedsnorkack
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Quote: Originally posted by woelen  | A fairly safe test for SO2 is using paper soaked with acidified KMnO4-solution. Dissolve a small amount of KMnO4 in 3...5% H2SO4. You get a dark
purple solution. Soak the paper with this and keep close to the flow of gas which is tested for SO2. If the gas is present the color of the KMnO4
fades. No need to fear dangerous reactions.
Do not store the test strips, prepare immediately before use. This is because KMnO4 quickly deteriorates when in contact with paper.
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I do not understand Sunrise's post in this context. Your black cloud of smoke definitely is not SO2. It most likely is carbon/charred material. Of
course, the smoke might have contained some SO2 as well.
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Is KMnO4 reduction in any way specific to SO2? Could H2S, or any organic gas, give a similar reaction?
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woelen
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H2S will give a similar reaction. Many organic gases will not give such a reaction, while others do. Volatile alkanes, chlorinated alkanes, carbonic
acid, esters, ethers and ketones do not give such a reaction. Volatile alcohols and aldehydes do give such a reaction.
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In the presence of water, H2S and SO2 cannot coexist for more than seconds, maybe a few minutes. Even very small amounts of water work
autocatalytically on the reaction:
2H2S + SO2 ---> 2H2O + 3S
The extra water, formed in the reaction works as a catalyst for further reaction. Just try it. Make some SO2 and some H2S and blow both gases into the
same container. You will see formation of a layer of sulphur on the walls of the container.
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