Description of experiment
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Needed compounds:
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potassium permanganate : KMnO4
sodium hydroxide : NaOH
methyl ethyl ketone : CH3 CO CH2 CH3
Class:
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elem=C
redox
Summary:
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MEK can be oxidized by potassium permanganate in alkaline environments (or
is this due to some impurities in the MEK?).
Description:
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Add some solid NaOH to some MEK: The solid does not dissolve.
Add some water (approximately the same volume as the volume of MEK): Two
colourless layers of liquid are formed. The solid NaOH dissolves. The
boundary between the two liquids is hard to observe, both liquids have
almost the same index of refraction.
Add some KMnO4: Part of the solid dissolves. The water-layer becomes green,
the MEK-layer becomes pink/purple. After a while of vigorous shaking the
two layers separate again. The top layer is almost colourless (pale pink),
the bottom layer is intense green.
Two hours later: The top layer (MEK) is colourless, the bottom layer (water)
is brown and opaque. It is filled with a thick layer of a brown precipitate.