Underwater Fireworks

More redox practice and another demonstration. I had tried this demonstration a few years ago with the Flinn Scientific kit but had been unsuccessful (as have many other chemistry teachers, according to my web search for answers). I was also concerned that chlorine gas was generated by the Flinn method. This time I went in a different direction. I placed about 12 mL of 18 M H2SO4 in the bottom of a large test tube, then layered an equal amount of ethanol on top. Clamped onto a ring stand, the ethanol heats up instantly. 0.5 grams of potassium permanganate are poured in and it sits on top of the sulfuric acid and more heat is generated. The reaction is as follows:

(1) KmnO4(s) + 3 H2SO4(aq) → K+ (aq) + MnO3+ (aq) + H3O+ (aq) + 3 HSO4- (aq)

(2) MnO3+ (aq) + MnO4- (aq) → Mn2O7 (s)

(3) Mn2O7(s) + CH3CH2OH(aq) → 2 CO2 (g) + 3 H2O(l) + 4 MnO2(aq)
 

Looked like lightning on the horizon. :)