Introduction:
When a drop of glycerol is added to crushed KMnO4 spread on a paper, a violent explosion occurs. This reaction is a classic example of a highly exothermic and rapid oxidation reaction.

Explanation:
The reaction between glycerol and potassium permanganate (KMnO4) is highly exothermic, meaning it releases a large amount of heat. This reaction is also known as the "Glycerol Explosion" or "Glycerol and Permanganate Reaction."

Reactants:
- Glycerol (C3H8O3): Glycerol is a colorless, odorless, syrupy liquid that is miscible with water. It is commonly used in various industries, including pharmaceuticals, cosmetics, and food.
- Potassium Permanganate (KMnO4): Potassium permanganate is a powerful oxidizing agent that is commonly used in laboratories for various purposes. It is a purple crystalline solid that dissolves in water to form a deep purple solution.

The Reaction:
When a drop of glycerol is added to crushed KMnO4 on a paper, the following reaction occurs:

C3H8O3 + 2KMnO4 → 3CO2 + 3H2O + 2MnO2 + K2CO3

Explanation of the Reaction:
- Glycerol (C3H8O3) reacts with potassium permanganate (KMnO4) to produce carbon dioxide (CO2), water (H2O), manganese dioxide (MnO2), and potassium carbonate (K2CO3).
- The reaction is highly exothermic, meaning it releases a large amount of heat energy.
- The heat generated by the reaction causes the rapid decomposition of the potassium permanganate and the production of gas (CO2).

Violent Explosion:
The rapid release of heat and the production of gas (CO2) results in a violent explosion. The explosion occurs due to the sudden increase in pressure caused by the release of gas. The explosion may also be accompanied by a crackling sound.

Conclusion:
When a drop of glycerol is added to crushed KMnO4 spread on a paper, a violent explosion occurs due to the highly exothermic reaction between glycerol and potassium permanganate. This reaction releases a large amount of heat and produces carbon dioxide gas, resulting in a sudden increase in pressure and causing the explosion.