Removing Tarnish from Silver Using an Electrochemical Cell
Description: A silver object that has been previously tarnished (over time or by placing in sodium sulfide) is cleaned by placing it in a pan containing aluminum foil, salt, baking soda, and boiling water. An electrochemical cell is produced between the silver sulfide and the aluminum to form silver and aluminum sulfide.
We can provide a tarnished silver electrode, or you can bring in a silver spoon, candlestick, or plate from home to clean for a more realistic demonstration.
Source: Institute for Chemical Education, Fun with Chemistry. A Guidebook of k-12 Activities
Year: 1993 Vol. 2 Page: 333 – 334
Keywords: Tarnish, Silver, Redox, Aluminum, Silver sulfide
Rating: 
Hazard: Some
- Acute toxicity hazard
- Electric shock hazard
- Scalding hazard
- Aquatic toxicity hazard
Effectiveness: Average
- Results are observable with guidance
- Somewhat connected conceptually to course material
- Mild effects are seen by audience
- Moderate failure rate
- Time to results is medium
Difficulty: Medium
- Some concerted or timed manipulations
- Reactions or demos at non-standard conditions
- Procedures with some intermediate steps to results
Safety Precautions:
- Eye protection required
- Gloves required
- Use of UL approved three-prong plug and outlet required
- Use of thermal gloves
- Perform in a well-ventilated area
- Absorbent materials on hand
- Prevent release of reagents to the environment
Class: Electrochemistry, Redox
Division: General
Home| General Chemistry Demos