zikki007
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KMnO4 and BaO2 reaction
I tried an experiment today with potassium permanganate and barium peroxide, I thought it will react similarly as potassium permanganate and hydrogen
peroxide , but it looks like something more is happening here... The barium peroxide started to dissolve with small fizzing in dilute potassium
permanganate solution and the solution colour changed from dark violet to dark blue and some sediment appeared too.
I think that dark blue colour can be a barium permanganate, sediment can be a manganese dioxide and the fizzing must be oxygen.
Is my suggestion right?
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LanthanumK
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I don't know why barium permanganate would be a different color than any other permanganate. Are you sure peroxide isn't behaving as a reducing agent,
making something like hypomanganate?
hibernating...
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zikki007
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I think it can be as you saying, I realized its rather a very dispelled blue particles in colorless solution - maybe barium hypomanganate? , but there
are also brown particles, so it must be manganese dioxide. It seems that this reaction is quite complex.
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LanthanumK
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At Wikipedia, it says that hypomanganates are made by reduction of manganates with hydrogen peroxide. It does not say anything about reduction of
permanganates with metal peroxides. You could always try one of the known syntheses at the potassium hypomanganate article and compare the results to
your experiment.
hibernating...
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AndersHoveland
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Unlike permanganate, manganates tend to be greenish blue. Barium manganate has a very low solubility. I really have no idea what is happening, but the
reaction might be:
(4)BaO2 + (4)KMnO4 + (2)H2O --> (4)BaMnO4 + (4)KOH + (3)O2
since hydrogen peroxide is known to act as a reducing agent toward permanganate
in addition, some Ba(OH)2 and MnO2 may also have formed
[Edited on 17-6-2011 by AndersHoveland]
I'm not saying let's go kill all the stupid people...I'm just saying lets remove all the warning labels and let the problem sort itself out.
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zikki007
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I try to crystalize it and see what comes out from the solution, if it doesn't decompose before it crystalize completely of course.
If I will get some crystals, I will put them to hydrochloric or dilute sulfuric acid. And the color, which will come out from it can finally say on
which oxidation state is the mangenese here.
I said last time is rather a very dispelled parcticles in water but it is really hard to say, it can be solution + these particles. Anyway I will let
it dry for a oxidation state test, becouse some unreacted KMnO4 can ruin the colour.
(4)BaO2 + (4)KMnO4 + (2)H2O --> (4)BaMnO4 + (4)KOH + (3)O2
This equation is looking good to me, the manganese dioxide which is also formed is probably only side reaction of decomposing KMnO4 in water and
reaction maybe speed up this decomposition a little bit.
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I puted the dry product to sulfuric acid and the colour was violet, and it is water soluable too. So it must be permanganate. I found an information
on some webstite that barium permanganate crystal are brownish-violet, so it can really be barium permanganate.
I have an idea to describe this reaction, but it can be totally wrong.
1) Maybe Ba(MnO4)2 is somewhat more stable than KMnO4.
So the reaction may be something like this:
(2)KMnO4 + BaO2 = Ba(MnO4)2 + K2O2
2) Potassium peroxide is decompossing in water to give potassium hydroxide and oxygen :
(2)K2O2 +(2)H2O = (4)KOH + O2
3) But before potassium peroxide is fully decomposed, it can reduce some of potassium permanganate and already formed barium permanganate, so there
can be quite lot manganese dioxide too and some barium hydroxide.
So that is my idea.
[Edited on 18-6-2011 by zikki007]
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