Dissolves kmno4 in ethanol

Experiment: lightning under water

Alcohol is easy to oxidize. This is how it reacts with potassium chromate. To do this, the mixture must be acidic. We know that from the classic breath alcohol test with the blowpipe, which turns green.

But the other well-known oxidizing agent in chemistry, potassium permanganate, also reacts with alcohol.

The formal redox reaction equations are for example:

Oxidation: CH3-CH2OH + H2O ———> CH3COOH + 4H+ + 4 e-

Reduction: MnO4- + 4 H.+ + 3 e- ———> MnO2 + 2 H.2O

(Of course, other oxidation products up to CO2 and H2Assume O.)

This reaction is quite spectacular (-> experiment). To do this, you layer alcohol with concentrated sulfuric acid and throw crystals of KMnO4 into it. They stay on the sulfuric acid layer. With the sulfuric acid, the anhydride of the unstable permanganic acid HMnO is formed4.

2 KMnO4 + H2SO4 ———> Mn2O7 + K2SO4 + H2O

This manganese heptoxide is a purple-colored gas that dissolves in alcohol. It is highly reactive and oxidizes the alcohol under the appearance of a flame. At the same time you can hear the small explosions, but here as a sharp "crack".

This can also be demonstrated by placing a spatula full of KMnO in a porcelain bowl4 a little sulfuric acid is added dropwise. A splendid purple-colored vapor forms. If alcohol or another flammable substance such as gasoline is dripped into it, it will deflagrate with the formation of brown manganese dioxide. Attention!

Caution is also required when pouring out the test mixture for the "lightning under water" when disposing of it. Then it can ignite, forming a huge fireball. It looks like a failed barbecue party.

Further texts on the subject of `` alcohol ''