The
ethylen gas of the previous experiments is sufficient
for 3 experiments: Testing with bromine water,
burning, testing with potassium permanaganate. For the third experiment
transfer 6 ml ethylen into a Liquemin bottle.
*
Left:
From a syringe add 1.5 ml diluted potassium permanganate solution to the
bottle with ethylen, shake . Observation
Photo
2: The pink colour disappears during mixing.
3. Photo: Add another 1.5 ml pink potassium permanganate solution.
Photo
rechts: The pink colour disappears again. This time a brown solid is
formed.
Explanation
to photo 1 and 2:
Ethylen (CH2=CH2) is oxidized by permanganate. The
alcohol ethane-diole HO-CH2-CH2-OH
is formed, while permanganate ions are reduced leaving colourless
manganese ions Mn2+(aq).
Explanation
to photos 3 and 4:
The second sample of ethylen was only sufficient to reduce potassium permanganate
to the stage of insoluble manganese dioxide MnO2(s).
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modification: 23.10.2001