Demonstration Risk Assessment
and Emergency Response Plan
Demo Name: Briggs-Rauscher Oscillating Reaction
Materials: 1.0 liter 3% hydrogen peroxide, H2O2
29 g potassium iodate, KIO3
1 liter distilled water
8.6 mL 6.0M sulfuric acid, H2S04 (To prepare 1.0 liter of stock solution, slowly and carefully pour 330 mL of concentrated [18M] H2S04 into 500 mL of distilled water. After the mixture has cooled, dilute it to 1.0 liter with distilled water.)
10.4 g malonic acid, CH2(CO2H)2
2.2 g manganese(II) sulfate monohydrate, MnS04·H2O
0.2 g soluble starch
2 1-liter beakers
hot plate
2 glass stirring rods
100-mL beaker
50-mL beaker
3-liter beaker
magnetic stirrer, with 2-inch stirring bar
Preparation:
Solution B-l. This is 1.0 liter of 3% hydrogen peroxide.
Solution B-2. Place 29 g of potassium iodate and approximately 400 mL of distilled water in a 1-liter beaker. Add 8.6 mL of 6.0M H2S04 to this mixture. Warm and stir the mixture until the potassium iodate dissolves. Dilute the solution to 500 mL with distilled water. This solution is 0.27M in KIO3 and 0.10M in H2S04.
Solution B-3. Dissolve 10.4 g of malonic acid and 2.2 g of manganese(II) sulfate monohydrate in approximately 400 mL of distilled water in the other 1-liter beaker. In the 100-mL beaker, heat 50 mL of distilled water to a boil. In the 50-mL beaker, mix 0.2 g of soluble starch with about 5 mL of distilled water and stir the mixture to form a slurry. Pour the slurry into the boiling water and continue heating and stirring the mixture until the starch has dissolved (1-2 minutes). The solution may be slightly turbid. Pour the starch solution into the solution of malonic acid and manganese(II) sulfate. Dilute the mixture to 500 mL with distilled water. This solution is 0.20M in malonic acid and 0.026M in MnS04.
Set the 3-liter beaker on the magnetic stirrer and place the stirring bar in the beaker.
Presentation:
Pour solution B-l and solution B-2 into the beaker on the magnetic stirrer. Adjust the stirring rate to produce a large vortex in the mixture. Pour solution B-3 into the beaker. (The nominal composition of this mixture is 0.050M malonic acid, 0.0065M Mn2+, 0.067M IO3-, 0.44M H2O2 and 0.025M H2S04.) The mixture will become amber almost immediately, and this color will gradually deepen. After 45-60 seconds, the mixture will turn deep blue. The blue will fade to colorless, and the cycle will repeat several times with a period which initially lasts about 15 seconds but gradually lengthens. After several minutes the solution will remain deep blue.
Demonstrator Safety Notes:
The demonstrator should wear goggles while performing this demonstration. Spectators should be kept at a distance of six feet.
Risk Assessment:
While some of these chemicals are hazardous in their pure states, the solutions used on this demonstration are quite dilute, so the hazard is reduced significantly. Sulfuric acid is corrosive. Malonic acid and the elemental iodine formed in this reaction are irritants. Hydrogen peroxide and potassium iodate are oxidizers. Chronic or large doses of manganese compounds may damage the nervous and reproductive systems. They have shown teratogenic effects in laboratory animals.
Emergency Response Plan:
If any of the liquids come in contact with the eyes, the eyes should be flushed with water for 15 minutes and medical aid should be sought.
If any of the liquids come in contact with the skin, the affected area should be washed with soap and water immediately.
In the event of a liquid spill, clean up using the Spill Containment Kit. Wear gloves while cleaning up the spill.