Migration of Copper (II) and Dichromate Ions
Description: Several drops of a brown solution are placed in a well cut into an agar gel. Two electrodes are connected to the terminals of 9V battery and inserted on either side of a Petri dish. Within a few minutes, the solution has migrated, and there is a blue and yellow band in the gel.
Source: Shakhashiri, B.Z. Chemical Demonstrations: A Handbook for Teachers of Chemistry
Year: 1991 Vol: 4 Page: 150
Keywords: Agar gel, Potential, Copper (II), Dichromate, Diffusion
Rating: 
Hazard: Medium
- Oxidizing solids
- Acute toxicity hazard- oral, inhalation, dermal
- Carcinogenicity hazard
- Skin corrosion hazard
- Serious eye damage
- Respiratory sensitization
- Germ cell mutagenicity
- Reproductive toxicity
- Specific target organ toxicity – single exposure – respiratory system
- Short term (acute) aquatic toxicity hazard
- Long term (chronic) aquatic toxicity hazard
Effectiveness: Average
- Mild effects are seen by audience
- Time to results is high
- Results are observable with guidance
- Good connection from demo to course material
- Moderate reliability
Difficulty: Medium
- Procedures with some intermediate steps to result
- Experiments in which display is necessary
- Some careful manipulations required
Safety Precautions:
- Eye protection required
- Gloves required
- Use UL approved three-prong plug and outlet
- Avoid exposures to droplets, mists, or vapors
- Perform in a well-ventilated area
- Prevent release of reagents to the environment
Class: Electrochemistry, Chromatography
Division: Analytical Chemistry
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