Description of experiment
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Needed compounds:
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acetone : CH3 CO CH3
cupric chloride dihydrate : CuCl2 . 2H2O
Class:
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elem=Cl,Cu
coordination
Summary:
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Anhydrous copper (II) chloride, when added to acetone, dissolves with a
yellow/brown color. If more copper (II) chloride is added, than can be
dissolved in acetone, then the remaining solid becomes red/brown, like iron
rust.
When the red/brown solid is added to water, then at once it becomes green and
then it dissolves, just as normal copper (II) chloride. The dilute solution
becomes light blue.
Description:
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Carefully heat some copper (II) chloride, dihydrate, until a dark brown solid
is obtained. Add some of this solid to acetone: Part of the solid dissolves,
the liquid becomes yellow/brown and clear. The part of the solid, which does
not dissolve settles at the bottom.
Let the liquid with the undissolved solid stand for a few days in a
well-stoppered test tube: The undissolved solid has turned red/brown, instead
of dark brown. Is this some complex of acetone with copper (II) chloride?
Decant the yellow/brown solution from the red/brown solid and let the solid
dry: The solid remains red/brown.
Add quite some water to the dry red/brown solid: The solid becomes green at
once, and then it quickly dissolves. The solution becomes perfectly clear and
light blue. No insoluble matter remains behind.
Remark: It might be that the red/brown color is caused by formation of a
complex of acetone and anhydrous copper (II) chloride, but this is just
speculation. More research on that is needed.