Description of experiment
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Needed compounds:
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hydrochloric acid : HCl
antimony : Sb
antimony sesquioxide : Sb2O3
sodium thiosulfate : Na2S2O3 . 5H2O
Class:
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elem=S,Sb
precipitation
Summary:
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A clock reaction that precipitates antimony sulfide.
Description:
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Dissolve six grams of antimony in 13mL of 20% hydrochloric acid and 2mL of
30% H2O2. If any antimony remains undissolved decant the liquid and leave
behind the solid particles. This solution should be mixed with a solution of
30g of sodium thiosulfate dissolved in 50mL of water. At first nothing will
appear to happen. Eventually a bright yellow precipitate of antimony sulfide
should precipitate.