Briggs-Rauscher Reaction
Materials
- 30% H2O2
- Soluble starch
- KIO3
- 1 M H2SO4
- MnSO4·H2O
- Malonic acid
- Water
- Stir plate and stir bar
- Graduated cylinders (3)
- Large beaker
- ~200 mL beakers (for preparation of solutions)
- Hot plate (for preparation)
Safety Precautions
- Ple
Demonstration
Preparation
- Prepare 100 mL of 9% H2O2 by diluting 30 mL of 30% H2O2 with 70 mL of deionized H2O in a graduated cylinder.
- Prepare an acidified 0.2 M KIO3 solution by adding 10 mL of 1.0 M H2SO4 to 80 mL of deionized water. Dissolve 4.3 g KIO3 in this solution and dilute to 100 mL in a graduated cylinder.
- Prepare starch solution by dissolving 0.1 g of soluble starch in 90 mL of boiling water. When cool, add 1.5 g malonic acid, 0.4 g MnSO4·H2O, stir and dilute to 100 mL in a graduated cylinder.
Presentation
- Add the H2O2 solution to a clean beaker fitted with a stir bar. Next, add the KIO3 solution and let the solutions mix thoroughly. Then, add the starch solution to the beaker, keeping the stir rod spinning. Upon addition of the final solution, bubbles should appear. The solution will turn yellow then blue,
then colorless. This reaction should oscillate for 5-10 minutes.