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Topic: H2SO4 oxidation mechanism  (Read 12575 times)

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Offline lutesium

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H2SO4 oxidation mechanism
« on: November 20, 2007, 10:41:48 PM »
Dear Sir/Ma'am

How does H2SO4 oxidize KBr to Br2??? Mechanism please


Lutesium...
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Offline AWK

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Re: H2SO4 oxidation mechanism
« Reply #1 on: November 21, 2007, 01:26:50 AM »
This is a very bad example of oxidation.
This reaction proceeds only  in 70 % H2SO4 (or over), and in fact this is reduction of H2SO4 by HBr at this very special conditions
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Offline Borek

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Re: H2SO4 oxidation mechanism
« Reply #2 on: November 21, 2007, 02:49:41 AM »
Please read forum rules.
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Offline lutesium

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Re: H2SO4 oxidation mechanism
« Reply #3 on: November 22, 2007, 11:23:37 AM »
No I don't think so!!! Because I've seen with my eyes that H2SO4 can oxidize KBr to Br2 at conc. lower than %30!!! I'm not telling you strictly that I'm right but I've done these rxns myself!!!
Can you give me a referance???
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Offline AWK

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Re: H2SO4 oxidation mechanism
« Reply #4 on: November 22, 2007, 01:04:17 PM »
It depends on source of H2SO4. It can contain some nitrogen oxide.
KBr can contain traces of KI. HI start react at 30 % of H2SO4.  You should check this possibilities
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Offline lutesium

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Re: H2SO4 oxidation mechanism
« Reply #5 on: November 22, 2007, 11:04:27 PM »
I don't know if they contain these but my H2SO4 was reagent grade Merck and my KBr was regular KBr!!! If they contain these with which mechanism they might help the oxidation???
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Offline AWK

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Re: H2SO4 oxidation mechanism
« Reply #6 on: November 23, 2007, 01:11:35 AM »
Mechamism of oxidation is rater ifficult in the case od inorganic compounds.
You may assume HBr is decomposing into H2 and Br2 (this is an equlibrium reaction). Then H2 reduces H2SO4. As the H2 disapperars , new molecules of HBr decompose.
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