With the Nitrogen Oxides and Acid Rain Environmental Chemistry Demonstration Kit, gases are bubbled into a large container of water containing an indicator. The water shifts from near neutral to highly acidic, the color change unmistakable.
When nitrogen and oxygen—the two primary components of the air we breathe—combine under certain conditions the results can be devastating. In this demonstration nitrogen oxides are generated by the dissolution of copper in nitric acid and the resulting gases bubbled into a larger container of water containing an indicator. As the water shifts from near neutral to highly acidic, the color change is dramatic and unmistakable. And just when the reaction appears to be complete…a breathtaking surprise! Accentuate your discussion of acid rain and its causes with this remarkable demonstration. Teacher Demonstration Notes included. Enough materials are provided to perform the demonstration seven times. Concepts: Environmental chemistry, acid–base indicators.
Time Required: 15 minutes
Materials Provided: Phenol red solution, nitric acid, filtering flask, Parafilm, plastic tubing, and rubber stoppers.
Note: Pre-1982 pennies and a large flask are needed but not provided. Perform this demonstration in a fume hood or well-ventilated lab.