localbroadcast
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hydriodic acid preparation in rhodium archive - is it viable?
I'm talking about this topic in the rhodium archive: 57% hydriodic acid
It utilizes hydroponic store sourced phosphoric acid and potassium iodide to produce 57% hydriodic acid. I was simply wondering if this is actually a
suitable method for the production of such a substance. I remember researching this subject a while ago and everyone was preaching about the
importance of using phosphorous acid, or hypophosphorous acid and that the phosphoric would not work.
Anyone have any insight? Thanks.
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Magpie
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Yes, this method works as advertised. Here's some information that will help on cleanup:
http://www.sciencemadness.org/talk/viewthread.php?tid=23257#...
The single most important condition for a successful synthesis is good mixing - Nicodem
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localbroadcast
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Great! Thanks for the information.
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woelen
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Quote: Originally posted by localbroadcast  | I'm talking about this topic in the rhodium archive: 57% hydriodic acid
It utilizes hydroponic store sourced phosphoric acid and potassium iodide to produce 57% hydriodic acid. I was simply wondering if this is actually a
suitable method for the production of such a substance. I remember researching this subject a while ago and everyone was preaching about the
importance of using phosphorous acid, or hypophosphorous acid and that the phosphoric would not work.
Anyone have any insight? Thanks. |
Phosphorous acid or hypophosphorous acid is needed if you want to make HI from iodine and water. In that case the iodine is reduced to HI by the acid.
If the acid is highly concentrated, then it might be that HI escapes as a gas from this reaction mix.
With phosphoric acid you do a simple replacement reaction. The H3PO4 is a highly non-volatile acid and this is in equilibrium with KI as follows:
KI + H3PO4 <---> HI + KH2PO4
The HI is a gas and escapes the system, hence driving the reaction to the right, even though HI is a strong acid and H3PO4 only is moderately strong.
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