Iodine Clock Reaction
Description: When two colorless solutions are mixed, there is no apparent reaction. After a short time period, the mixture suddenly turns almost black. Variations illustrate the kinetics of the reaction.
Source: Shakhashiri, B.Z. Chemical Demonstrations: A Handbook for Teachers of Chemistry
Year: 1991 Vol. 4 Page: 16
Keywords: Kinetics, Concentration, Reaction rate, Induction period, Clock
Rating: 
Hazard: Medium
- Acute toxicity hazard – oral
- Skin irritation
- Eye irritation
- Inhalation hazard
- Electric shock hazard
- Burn hazard
- Aquatic toxicity hazard – acute
Effectiveness: Good
- Results are clearly observable without guidance
- Clear contrast between behavior of systems
- Time to results is medium
- Low failure rate
Difficulty: Medium
- Some sequential or timed manipulations
- Reaction at non-standard conditions
- Prior training recommended
- Procedures with some intermediate steps
Safety Precautions:
- Chemical gloves required
- Thermal gloves recommended
- Use UL approved three-prong plug and outlet
- Absorbent material on hand
- Sodium bicarbonate on hand
- Prevent release of reagents to the environment
Class: Kinetics
Division: General
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