ACTIVITIES OF METALS
The objective of this experiment is to rank order several metals on the basis of their chemical activity.
This experiment is appropriate for a general or first-year college-prep course. Active metals react with acids to produce hydrogen gas. The rate at which bubbles of hydrogen are produced when various metals are placed in acid solution can be used to indicate the reactivity of the metals.
Approximately 30 minutes.
Concentrated solutions of HCl will burn skin and damage clothing. Fumes from acid can be caustic and/or irritating; do this experiment in a well-ventilated area (hood, if available). Goggles must be worn throughout this experiment.
- iron nail
- galvanized nail
- copper tack
- aluminum nail
- 6 M HCl solution (500 mL concentrated HCl solution diluted to 1.00 liter with distilled or deionized water)
- test tubes or small beakers*
- HCl solution is available from a hardware store as muriatic acid, 28% solution; this solution is approximately 8 M and may be substituted for 6 M HCl solution.
- Styrofoam cups or small glass jars may be used in place of test tubes or small beakers.
Dilute the acid with water and flush down the drain with water. Metal pieces can be discarded with solid waste.
Active metals react with acids to produce hydrogen. In the reaction, the metal is oxidized while the H+ from the acid is reduced to H2(g). The most active metals are the most easily oxidized.
- Place a different metal in each of four test tubes and add just enough 6 M HCl solution to cover the metal.
- Record the relative activity of each metal based upon the rate at which hydrogen is released.
- Test the gas released by the galvanized nail with a burning splint to confirm that it is hydrogen.
- Rank the four metals from lowest to highest activity.
- Some metals form an oxide coating on the surface that will prevent further oxidation; these should be cleaned with steel wool before testing their reactivity. Even though the metals chosen for this experiment may have an oxide coating, they should give the correct order of activity without cleaning because of the large differences in activity.
- Have students answer the following questions after completing this experiment: What is one problem associated with acid rain that is illustrated by this experiment? What other problems are associated with acid rain? Some metals are galvanized to prevent "rusting." If zinc reacts with acid readily, as discovered in this experiment, why is iron coated with zinc? How could this hypothesis be tested in the laboratory?
Submitted by Annis Hapkiewicz
Woodrow Wilson Leadership Program in Chemistry
The Woodrow Wilson National Fellowship Foundation
CN 5281, Princeton NJ 08543-5281