giacobinozeta
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Hbr
when I try to distill my fresh made Hbr (from h2so4 and kbr) it distill at costan 120 C. I´m sure that the thermometer is rigth because I distill
anethole, water etc at the literature bp.
Is there an azeotrope of Hbr boiling at 120 C? What could that else be, bromine water?
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BromicAcid
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http://www.sciencemadness.org/talk/viewthread.php?tid=2169
Your answer could have very easily been looked up via google by searching "HBr azeotrope" or on this forum by searching hydrobromic acid.
[Edited on 1/7/2005 by BromicAcid]
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giacobinozeta
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distilling
thanks for the answer.
My reference says 48% HBr boils at 126 C and not at 122.5.
My problem is that the fucked temperature does not reach 122.5 or 126 but only 120 C.
Is maybe the thermometer bad?
How can I test the "Hbr" to be sure ?
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BromicAcid
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Do you just want to know if it is HBr of if it is of a certain precentage? If it is a clear liquid like mine was from this reaction, adding some
peroxide will turn it yellow then red and if it is concentrated make elemental bromine appear in the bottom of a test tube. I think that is pretty
indicitive of HBr.
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giacobinozeta
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Hbr
Yes, this is a idea,
with peroxide or permanganat to liberate bromine.
My first question is: Could be that Hypobromous acid?
the second is how do I test the concentration.
Thnaks in advanced.
(Yes is very clear and after stayng in Light exposure turn sellow and then red)
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BromicAcid
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None of the oxoacids of bromine are distillable at atmospheric pressure, some can be distilled under massively reduced pressure although they still
suffer significant decomposition. So as long as it is not red from dissolved bromine, and bearing in mind the sulfuric acid will not distill over,
your solution almost entirely a solution of hydrobromic acid. Test the concentration as you would any acid, you can get a rough calculation via the
density of the solution although you need a table, a titration would probably give the best results, HBr is a strong acid so you could get a pH
reading, assume full dissociation, then work to the hydrogen ion concentration and from there get the concentration of the HBr.
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giacobinozeta
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Hbr
also standard tritation would do the job?
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BromicAcid
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Yes it would, I mentioned that above.
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