Skip to main content

Reaction of Potassium Chlorate and Sucrose


Demonstration Cart with Plastic Shielding

Fireproof Fiberglass Pad

Large Watchglass

Safety Shield

Small Bottle of Potassium Chlorate and Sucrose Mixture

Sulfuric Acid 18M

1 mL Plastic Dropper

Glasses and Goggles


Advanced Preparation

Mix 12g Potassium Chlorate (KCl03) and 4g Sucrose  together with a large mortar and pestle.  Make sure the powder is well combined and all lumps are ground out.  Place this mixture in a small bottle.



  1. Place a watchglass on a fireproof fiberglass pad.  Do this demonstration on the cart with the safety shielding, and then place the small safety shield in front.
  2. Pour the mixture of Potassium Chlorate and sucrose onto the watch glass
  3. Add 1 drop of concentrated sulfuric acid to the mix and step back.
  4. Reaction start slowly, then bursts into flame with lots of smoke.
  5. Wait for applause.
Note: Do not do this demo in a room without lots of ventilation.        


The stoichiometry of the reaction is not known. It has been reported that chloric acid (ClO3) is formed when KClO3 and H2SO4 are mixed and that chloric acid decomposes organic substances very rapidly, often with inflammation.


Waste Management

The contaminated watch glass should be bagged and given to EH&S as hazardous waste (Toxic Solid Oxidizer).