Chem Expt 7 : Lightning in a Test Tube

Permanganate reacts with sulfuric acid to produce manganese heptoxide that explodes on contact with alcohol.
MATERIALS REQUIRED :
95% Ethanol
Concentrated sulfuric acid
Potassium permanganate crystals
Test Tube (Borosil)
HOW TO DO IT :
1. Pour concentrated sulfuric acid (2-4 ml) in a test tube.
2. Carefully add ethanol on top of sulfuric acid and prevent them from mixing.
3. Drop a few crystals of potassium permanganate into the test tube and switch off the light.
4. Wait and watch the effect !
5. When the demonstration is concluded, inactivate the reaction by placing the test tube into a large water. Be very careful ! There is a chance of damaging explosion.
At first the permanganate ion dimerizes (by protonation and then dehydration ) into the extremely more reactive dimanganese heptaoxide (Mn2O7) :
MnO4- + H+ = HMnO4
2 HMnO4 = Mn2O7 + H2O
(Concentrated sulphuric acid absorbs water and shifts equilibrium to the right).
The produced Mn2O7 vigorously oxidises ethanol to carbon dioxide with a crackling fire :
C2H5OH + 2 Mn2O7 = 2 CO2 + 4 MnO2 + 3 H2O

SAFETY PRECAUTIONS :
This experiment is extremely dangerous as it involves corrosive Sulfuric acid, flammable ethanol, and a chance of glassware shattering as a result of the vigorous chemical reaction. So this experiment should only be performed under the supervision of an experienced chemist, wearing eye-protective Lab-spectacles, face protective clothes and using proper safety precautions.
(Ref : A new procedure for the lightning experiment: Mn2O7 and ethanol : https://www.researchgate.net/publicat...
The author is grateful to You Tube Audio Library for providing the background music Digital Solitude by Silent Partner.

Видео Chem Expt 7 : Lightning in a Test Tube канала Dr.Amal K Kumar