Description of experiment
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Needed compounds:
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sodium bromide : NaBr
sulphuric acid : H2SO4
potassium chlorate : KClO3
potassium bromate : KBrO3
Class:
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elem=Br,Cl
redox
Summary:
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Bromates are more reactive than chlorates in dilute aqueous solutions.
Description:
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Add a solution of NaBr to
1) a solution of KBrO3 in dilute H2SO4 (appr. 1 mol/l)
2) a solution of KClO3 in dilute H2SO4 (appr. 1 mol/l):
Result 1:
Quick formation of Br2, liquid also becomes slightly turbid, but it looks as
if this is something different than Br2. This may be solid NaHSO4 or another
alkali sulfate.
Result 2:
No visible reaction. Only when the liquid is heated, some bromine is formed.
A good yield of Br2 is not obtained until the liquid is heated close to the
boiling point of water.