Odyssèus
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Iodides and ozone
I have read that the test for ozone with alkali iodides is this reaction:
2 KI + 2 O<sub>3</sub> => 2 K<sub>2</sub>O + 2 O<sub>2</sub> + I<sub>2</sub>
I am curious if the reaction would work with the chlorides of the alkali metals as well (Less expensive)? With an inert gas to carry away the iodine
or chlorine, could this could be used to make the oxides of the alkali metals in an appreciable amount without burning the pure metal?
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12AX7
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Oxygen is more electronegative but I would be inclined to think you'll run into activation problems...namely the stability of salt. It would work in
solution, but then, you'd need a whole lot of ozone to remove the chlorine.
I think the usefulness of iodine is its strong color. Iodized salt has all of 50ppm or so iodide in it, but iodized salt moistened with a bleach
solution turns yellow/brown.
Tim
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Mr. Wizard
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Potassium Iodide /Starch paper is used as a test for ANY oxidizer. The KI/starch paper is moistened with dilute HCl and exposed to the gas, liquid, or
solid, and most oxidizers will give a blue black starch/iodine stain. I have seen it work on bleach, nitrates, chlorates, chlorine, ozone, MnO2,
peroxides, and organic peroxides. In short, just about anything that will liberate Cl2 from the HCl which then liberates the I2 from the KI. Some
oxidizers will then continue and destroy the starch and paper, so the color may not last very long.
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unionised
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I think that's an "iealised" equation. For a start, iodine reacts with strong bases (Like K2O). For an encore the starch/KI paper type reaction is
usually done in weakly acid solution.
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Odyssèus
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Sounds like the reaction is for example:
KI + HCl => KCl + HI
6 HI + O<sub>3</sub> => 3 H<sub>2</sub>O + 3 I<sub>2</sub>
Not:
2 KI + 2 O<sub>3</sub> => 2 K<sub>2</sub>O + 2 O<sub>2</sub> + I<sub>2</sub>
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JohnWW
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That reaction of KI with O3 is probably too simplistic. Other likely products, especially with an excess of O3, would include K2O2, KO2, KO3 (which
like K2O would be instantly hydrolysed to KOH and the peroxide anion on contact with water, with some liberation of O2), and also I2O, I2O3, I2O5 (and
in the presence of water, HIO3 and H5IO6).
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Odyssèus
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Either way... the electronics I was trying to rig up for a silent discharge tube mysteriously died without seeming hot/fuse burning out etc. Guess I
wolnt be able to test it for awhile. 
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