Draeger
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Toxicity of SO2
So, right now, I am planning to do the carbon snake demonstration (H2SO4 and sugar), but I was wondering how toxic SO2 is? Would the amount generated
from H2SO4 with max. 20g of sugar be enough to be toxic? And how do I know when the concentrations of gasses approach certain concentrations in
general, or rather when do I know that the concentration is dangerous?
Collected elements:
Al, Cu, Ga, C (coal), S, Zn, Na
Collected compounds:
Inorganic:
NaOH; NaHCO3; MnCl2; MnCO3; CuSO4; FeSO4; aq. 30-33% HCl; aq. NaClO; aq. 9,5% ammonia; aq. 94-96% H2SO4; aq. 3% H2O2
Organic:
citric acid, sodium acetate, sodium citrate, petroleum, mineral oil
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woelen
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I would not do the experiment inside, unless you have a good fume hood. You do not only get SO2, but also fumes of H2SO4 in the air, due to the
extreme heat of the reaction. The total mix of fumes is very corrosive and extremely choking. If you do the experiment outside and you accidently
inhale a small whiff of the fumes, then there will be no real problem, but inside, the fumes will linger for too long a time and it will corrode
materials and may become harmful for health as well.
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B(a)P
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The odour threshold for SO2 (1 ppm) is about 100 times less than the concentration considered to be immediately dangerous to life and health (100
ppm). So once you can smell it you know the concentration is heading in the wrong direction with a decent buffer. The problem you don't know if you
are smelling 1 ppm or 100 ppm. Take a look at the ASTDR Toxicological Profile for SO2 for more info.
If you don't have any ventilation you are likely to exceed 100 ppm with that reaction mass, you will definitely need good ventilation.
You can make a reasonable SO2 detector for around $50 AUD if you know what you are doing with electronics.
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Draeger
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Quote: Originally posted by woelen  | | I would not do the experiment inside, unless you have a good fume hood. You do not only get SO2, but also fumes of H2SO4 in the air, due to the
extreme heat of the reaction. The total mix of fumes is very corrosive and extremely choking. If you do the experiment outside and you accidently
inhale a small whiff of the fumes, then there will be no real problem, but inside, the fumes will linger for too long a time and it will corrode
materials and may become harmful for health as well. |
| Quote: Originally posted by B(a)P | The odour threshold for SO2 (1 ppm) is about 100 times less than the concentration considered to be immediately dangerous to life and health (100
ppm). So once you can smell it you know the concentration is heading in the wrong direction with a decent buffer. The problem you don't know if you
are smelling 1 ppm or 100 ppm. Take a look at the ASTDR Toxicological Profile for SO2 for more info.
If you don't have any ventilation you are likely to exceed 100 ppm with that reaction mass, you will definitely need good ventilation.
You can make a reasonable SO2 detector for around $50 AUD if you know what you are doing with electronics. |
Thank you. I'll be trying this once I can manage to get a fume hood from somewhere then.
Collected elements:
Al, Cu, Ga, C (coal), S, Zn, Na
Collected compounds:
Inorganic:
NaOH; NaHCO3; MnCl2; MnCO3; CuSO4; FeSO4; aq. 30-33% HCl; aq. NaClO; aq. 9,5% ammonia; aq. 94-96% H2SO4; aq. 3% H2O2
Organic:
citric acid, sodium acetate, sodium citrate, petroleum, mineral oil
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Texium
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You should be able to do it outside without issue.
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morganbw
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I have done this, more than once, with no notice of odor at all.
I am not saying this is always the case but it was with me.
But for sure, some things should not be done inside.
Edited to add: If you have ever made a sodium/potassium metabisulfite solution you have breathed a little SO2
[Edited on 4/14/2020 by morganbw]
[Edited on 4/14/2020 by morganbw]
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j_sum1
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I have seen the sugar-H2SO4 experiment done indoors plenty of times and also done it myself.
Sure there are fumes, but these seem to be decomposition byproducts as much as anything. I have never noticed any SO2 smell. I am not advocating
doing this in an enclosed space or putting your head over and inhaling. In a large enough space I think it is probably ok.
I would recommend doing a trial run outdoors and then you know what to expect if you need to do it inside a lab. You can then scale as appropriate.
Bear in mind that at small scale the temperature will be a lot lower. Conversely, at a larger scale you will get a lot more charring and carbon smoke
from the higher temperature.
In terms of SO2, I think that a sulfur candle is far more dangerous. But with appropriate measures, I have done this inside also simply by sucking
the gases through a NaOH scrubber.
If you are just after a snake experiment, there is a good one you can do with a mixture of powdered sugar, sodium bicarbonate and alcohol. It is
slower than the regular pharaoh's serpent but still dramatic. https://www.youtube.com/watch?v=Hibxz9_ZW18
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Sulaiman
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In my limited experience with SO2,
you will run away coughing long before dangerous exposure occurs.
In the sugar + sulphuric acid snake experiment I've never noticed SO2
but I have noticed sulphuric acid vapour.
CAUTION : Hobby Chemist, not Professional or even Amateur
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Shiva_Inorganic
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Sulfur dioxide is moderately toxic. At low concentrations, it does not cause any serious or noticeable health issues. Only certain experiments produce
a significant concentration of SO2. Burning sulphur, treating metabisulfites with acids will produce copious amounts of SO2. It will cause suffocation
even at low to moderate concentrations. Chronic exposure to SO2 can cause acute respiratory ailment. SO2 will not cause any immediate danger to life
unless we exposure ourselves to sources that release very large amounts of SO2 (volcanic activities, industrial activities etc.)
- Shiva Chemist
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