budullewraagh Posted December 8, 2004 Posted December 8, 2004 i got a red gas. smelled bad. not a good thing if it's in your room. what could this be?
MulderMan Posted December 8, 2004 Posted December 8, 2004 were you trying to make Iodine with that reaction? KI + H2SO4 ---> HI + KHSO4, the HI is the gas made, which i would have thought to be around the violet colour. just a guess anyway.
jdurg Posted December 8, 2004 Posted December 8, 2004 Possibly some bromide contamination in your potassium iodide. Bromine is VERY volatile, much more so than iodine, so if any was generated it would quickly evaporate into the distinct, red/brown/orange vapor.
budullewraagh Posted December 8, 2004 Author Posted December 8, 2004 god damn. it was red/brown/orange. i also got the characteristic hydrogen sulfide rotten egg smell
budullewraagh Posted December 8, 2004 Author Posted December 8, 2004 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
Silencer Posted December 8, 2004 Posted December 8, 2004 Well if you're talking to us now it can't be that bad, can it? I'd be more worried about what's in your room at this point.
budullewraagh Posted December 8, 2004 Author Posted December 8, 2004 actually, it very well could be, considering the possibility of me getting pneumonia tomorrow. left in the beaker was a red solution. could this be any combination of Br3 and I3 anions?
Gilded Posted December 9, 2004 Posted December 9, 2004 "i got a red gas. smelled bad. not a good thing if it's in your room." You just threw in KI and H2SO4 without even thinking about what might come out of it?
YT2095 Posted December 9, 2004 Posted December 9, 2004 erm... WHY did you use 97%? 50% would have been perfect! you actualy Forced a reaction that should have required heat at 50%, it dehdrated water of crystalisation in the KI and spontaniously reacted. Dumb! (but funny LOL) ) there`s no Bromine, just HI(g) and yes there will be some H2S in there as the lot decomposed with a few side reactions. don`t worry about that tho, you`re alive enough to have typed this, you`ll live
jdurg Posted December 9, 2004 Posted December 9, 2004 Well, I wouldn't be so sure about saying that there's 'no' bromine. Depending on the purity of the KI that was used, there's a very good chance that there would be some KBr contamination. The H2SO4 would undoubtably oxidzie the Br- into elemental bromine. So some of the red/brown/orange gas may have been bromine vapor.
YT2095 Posted December 9, 2004 Posted December 9, 2004 well it would have to be a REALLY low grade KI supply then I have a bottle oh HI(aq) here and it`s Deep brown/Orange colored
jdurg Posted December 9, 2004 Posted December 9, 2004 Ahh yes. Marvelous how hydroiodic acid can oxidize its own ions into elemental iodine.
YT2095 Posted December 9, 2004 Posted December 9, 2004 funny you should say that! if left alone long enough without a good shake, you do get elemental Iodine form on the inside of the cap begs the question where the Hydrogen goes though?
MulderMan Posted December 9, 2004 Posted December 9, 2004 so i was sort of right about the HI, i wasnt sure because ive only seen that reaction done with sodium iodide, but there all alkali metals! the whole reaction hasnt worked for me before though to make pure iodine, the HI is supposed to be oxidised by left over sulphuric acid, so i should have iodine n SO2? any tips on how to get it right, im not sure how pure 'ebay' samples are.
YT2095 Posted December 9, 2004 Posted December 9, 2004 I`m familiar with that method too, such as here: http://www.webelements.com/webelements/elements/text/I/key.html KI works just as well, and I srongly suspect that much of what was considered large amoungs of H2S was infact SO2 also, as I said, there are quite a few side reactions that take place from the HI stage, I`de THEN do the Cl gas method, taking off the I(g) sublimate as it`s produced. it`s just personal prefs though
jdurg Posted December 9, 2004 Posted December 9, 2004 Here's a quick question. Would it be possible to take a solution of iodide ions and add hydrogen peroxide to it to oxidize the I- back to I2? If this could work with the store-bought 3% H2O2, that might wind up being a safer, easier method of manufacturing iodine.
YT2095 Posted December 9, 2004 Posted December 9, 2004 the H2O2 method does work, it requires pressure if I rem right tho???? (I could be wrong here)
jdurg Posted December 9, 2004 Posted December 9, 2004 Hmmm. I'll have to give that a test. I'll try and pick up some KI sometime soon and put some crystals of it into some H2O2. I know that it will cause the rapid decomposition of the peroxide into water and oxygen, but I'll try and see if the solution starts turning colors. If that does work, then it would be a fantastic way of producing iodine in the home. (Though I'm now starting to think that it's not that simple since if it was, people would have already known about it). Let's see what google has to say.
jdurg Posted December 9, 2004 Posted December 9, 2004 Okay. Under normal conditions, very little, if any iodine will be formed since the first step in the reaction is the formation of the IO- ion which then further reacts with the peroxide forming the I- ion again. So with just hydrogen peroxide and KI, the KI is only a catalyst. However, if the reaction medium is acidic, pure iodine is formed. I've heard that you really only need 1.0 molar sulfuric acid, though I believe that acetic acid would work as well. So maybe one should try dissolving some KI in some concentrated vinegar, and then adding some regular H2O2 to that.
budullewraagh Posted December 10, 2004 Author Posted December 10, 2004 works best with sulfuric acid, though, as you oxidize the iodide from hydroiodic acid, which causes a much greater yield
budullewraagh Posted December 12, 2004 Author Posted December 12, 2004 begs the question where the Hydrogen goes though? perhaps atmospheric oxygen acts as a base and accepts the hydrogen i think i'll finish that reaction later today. as it is, the solution looks brominated; i believe i can see aqueous tribromide/triiodide anions as well as aqueous elemental iodine (only aqueous because of presence of aqueous potassium iodide). as it is i think it has been acidified enough so i'll just add the 35% hydrogen peroxide and let it be done. good idea? oh, and i think i'll do it outside this time so as not to breathe in anymore bromine:\
YT2095 Posted December 12, 2004 Posted December 12, 2004 why not start with pharmaceutical grade KI? or tincture tho? that`s all I do and I get perfect HI results
Guest sholin Posted December 19, 2004 Posted December 19, 2004 I have a reaction like that one" KI + Al(HSO4)3-------> a violet color solution Waht reaction may occur? please help me!
budullewraagh Posted December 19, 2004 Author Posted December 19, 2004 yt, tincture isnt cheap at all and i wanted quality reagents. sholin, try adding more bisulfate. if you lose the violet solution and see iodine crystals settle, you had a solution of iodine and potassium iodide
YT2095 Posted December 19, 2004 Posted December 19, 2004 you`ll get no better than Phamacuitical grades for a reagent Technical grade, Reagent Grade, Pharmacuitical grade, what would be your choice? I know what mine would be
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