budullewraagh
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97% Sulfuric acid + KI
i got a red gas. smelled bad. not a good thing if it's in your room.
what could this be?
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BromicAcid
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It should go like this:
2KI + 2H2SO4 ---> I2 + SO2 + 2H2O + K2SO4
However this does not explain a red gas. The bad smell of course from SO2, H2S as a by product, and I2. Elemental sulfur could have been formed
which could have caused some aspect of the color, sulfur and iodide are not known to form any compounds so although sulfur halides are colorful
liquids / gasses this really isn't a possibility here.
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budullewraagh
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that fucking blows. i heard that adding sulfuric acid to potassium iodide yielded hydroiodic acid and potassium bisulfate or potassium sulfate. i
was going to then add hydrogen peroxide to oxidize the iodide
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budullewraagh
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how worried should i be? i saw the gas, held my breath, put it in my window and ran
im nervous as hell, as i got a sniff of it
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budullewraagh
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oh, by the way, i contacted some associates who say some of the gas (which was indeed red/brown/orange) was bromine from impurities in my KI
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budullewraagh
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i was left with a red solution. is that the tribromide anion?
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BromicAcid
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How did you get a major bromine impurity in your potassium iodide? The red color is probably just due to elemental bromine, I'm not that
firmilar with the tribromide anion, I don't think it forms to such a large extent as the triiodide anion so it's not as widely covered. But
it could be, or maybe some inner halogen compound, or some bromine sulfur compound. Could be a mess of things, heating would drive off volatiles and
give you an idea of the permanace of the solution in terms of the colorants present and what might be causing them.
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Marvin
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I think you may be invoking bromine where it isnt needed. Sulphuric acid + KI would most likley produce a lot of HI gas with a sizable amount of
decomposition to iodine colouring it brown.
Depending on the light, brown and a dark red can be interchangable. Orange is rather common for more dilute solutions and particually tends to stain
plastic bottles. Iodine also takes a wide variety of colours including a rather nice purple depending on the solvent its in.
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unionised
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Off hand, the only red gas I can think of is iodine vapour. Since that is one of the products of the reaction, I think it would be a reasonable guess
that that is what you got.
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neutrino
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I doubt its iodine. Iodine vapor is deep purple (very beautiful, IMO). Besides that, iodine’s vapor pressure is rather low at room temperature.
Yes, the tribromide ion is a possilility. I have made it and it is reddish.
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budullewraagh
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i just finished the reaction outside in a cold setting. a mouse knocked over my beaker, as i found out. i still had a bunch of solid left over, so
i finished the reaction. i first added water to make it all aqueous. then i added 35% hydrogen peroxide and nothing happened. at all. any ideas as
to what the hell is going on?
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unionised
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"Yes, the tribromide ion is a possilility. I have made it and it is reddish."
I'd be intrigued to hear about any volatile compounds of it that are reddish. Not only that, but I still wonder through what nuclear reactions
you are transmuting any of the elements present into bromine.
If there was bromide present and it was oxidised to bromine then the next thing to happen would be 2KI +Br2--> 2KBr + I2
or are you postulating that not only is there some mystery source of bromine, but that there's also no iodide?
Whether you consider iodine to be red rather than purple, violet or any other description is a matter of opinion and lighting.
[Edited on 21-12-2004 by unionised]
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