English: Demonstration of disproportionation reaction. Few drops of ethanol are added to a small pile of ammonium dichromate ((NH₄)2Cr₂O₇) and ignited. Sparks are emitted and an ash-like product is formed. The phenomenon resembles the eruption of a volcano. Actually, this is a disproportionation reaction in which ammonium dichromate (orange) decomposes to chromium(III) oxide (green). The reaction starts at 180 °С, becoming self-sustaining at approximately 225 °С. The chemical equation is:

(NH₄)2Cr₂O₇(s) = Cr₂O₃(s) + 4H₂O(g) + N₂(g).

Planned and performed by Marina Stojanovska, Miha Bukleski and Vladimir Petruševski, Department of Chemistry, FNSM, Ss. Cyril and Methodius University, Skopje, Macedonia.