Description of experiment
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Needed compounds:
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sulphuric acid : H2SO4
sodium borohydride : NaBH4
vanadyl sulfate : VOSO4.5H2O
Class:
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elem=V
redox
Summary:
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Vanadium in the +4 oxidation state is not reduced to vanadium in a lower
oxidation state by borohydride.
Description:
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Add a solution of NaBH4 to a solution of vanadyl sulfate: The liquid slowly
becomes turbid and grey. The precipitate is very finely divided. The liquid
also starts foaming vigorously. The evolved gas is H2.
Add an excess amount of dilute H2SO4: Vigorous evolution of H2. The liquid
becomes clear again and blue, the color of [VO]2+.