The acid-base indicators phenolphthalein, crystal violet, and bromphenol blue turn various bright colors in basic solutions. Surprisingly, these colors will eventually fade if the solution is too basic! In this technology-based experiment, students analyze the kinetics of these “fading” reactions by measuring the absorbance or intensity of the specific indicator's color as a function of time. Graphing the results reveals how the rate of the fading reaction depends on the concentration of the indicator—1st order or 2nd order. Includes Teacher Notes, extensive background material, and reproducible student handouts.
Complete for 30 students working in pairs. Spectrophotometer or colorimeter is required.
Additional ResourcesNo Additional Resources at the time.
Flinn Catalog/Reference Manual Page 468
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