Iodine Clock Reaction
Materials
3 500mL Erlenmeyer Flasks with Stir Bars
3 Stir Plates
6 Bottles of Solutions (Mix 1 with 2, 3 w/ 4, and 5 w/ 6)
Gloves and Goggles
Solutions
- Solution A: 2gm KIO3 in 1 liter H2O
- Solution B: Dissolve 2gm soluble starch in 500ml boiling water,
- add 0.4gm NaHSO3 + 5ml 1.0M H2SO4,
then bring up to 1 liter.
Procedure
- Mix equal volumes A + B with stirring.
- Varying volumes gives different times.
- 1) 160ml A
2) 160ml B -
3) 80ml A + 160 ml H20
4) 80ml B - 5) 40ml A + 240ml H20
6) 40ml B
- 1) 160ml A
- Mixing 1 + 2, 3 + 4, and 5 + 6, gives relative times of 1, 0.5, 0.25.
Reactions
IO3- + 3HSO3- --> I- + 3SO42- + 3H+
6H+ + IO3- + 5I- --> 3I2 + 3H2O
I2 + starch --> (blue)
Waste Management
The solutions should be collected in a bottle and sent to EH&S as Hazardous Waste (Toxic)