Description of experiment
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Needed compounds:
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sodium metaperiodate : NaIO4
hydrochloric acid : HCl
praseodymium chloride : PrCl3
Class:
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elem=I,Pr
precipitation
Summary:
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Praseodymium ions form a very light green precipitate with periodate, which
almost completely dissolves on heating.
Description:
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Prepare a solution of sodium metaperiodate and a yellow solution of PrCl3 in a
small excess amount of HCl and add these two solutions to each other:
Immediately, a very pale green (almost white) precipitate is formed.
Heat the liquid with the precipitate and boil for a short time: Most of the
precipitate dissolves and the liquid only remains opalescent, not really
turbid.
Let cool down: A dense precipitate has settled at the bottom. This precipitate
is light, but it has a definite light green color.