Description of experiment
Below follows a plain text transcript of the selected experiment.
Needed compounds:
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hydrochloric acid : HCl
potassium dichromate : K2Cr2O7
antimony sesquioxide : Sb2O3
Class:
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elem=Sb
redox
Summary:
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Antimony (III) is oxidized by dichromate in acidic environments.
Description:
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Add some Sb2O3 to some hydrochloric acid (appr. 10% by weight): The solid
dissolves and the liquid becomes colorless and almost clear.
Add some crystals of K2Cr2O7 and shake: The crystals dissolve and the liquid
becomes green. The orange dichromate is reduced to green chromium (III).
Add a large quantity of water: The liquid becomes white and milky, the Sb (III)
ions are hydrolysed on dilution of the acid.