A Fresh Look at the Crystal Violet Lab with Handheld Camera Colorimetry

Chemical kinetic experiments to determine rate laws are common in high school and college chemistry courses. For reactions involving a calor change, rate laws can be determined experimentally using spectrophotometric or colorimetric equipment though this equipment can be cost prohibitive. Previous work demonstrated that inexpensive handheld camera devices can be used to quantify the concentration of a colored analyte in solution. This paper extends this approach to the kinetic study of the color fading of crystal violet upon reaction with sodium hydroxide. The results demonstrate accurate determination of the reaction order, with respect to crystal violet, using a method accessible in many high school and college laboratories.