Determination of Kinetic Constant of Methyl Violet with Sodium Hydroxide Using Smart Phone

The chemical reaction rate is the basic concept of reaction kinetics, and chemical kinetic experiments to determine rate laws are common in college chemistry laboratory courses. However, there are many shortcomings in this experiment, with the large consumption of reagents as one of them. Starting from the concept of green chemistry, we propose to combine the color theory with chemical knowledge, so as to save the reagents used in the experiment and improve the students’ interest in the experiment. In this paper, we first conducted a survey to investigate the subjective evaluation on classical kinetics experiments and the willingness to do virtual chemical experiments with smart phones. After analyzing the feasibility of the method in theory, we shot a short video of the reaction of methyl violet with sodium hydroxide, and determination of the kinetic constant using colorimetric analysis. The method combines the complementary color theory and Lamber-Beer law, and a dynamic experiment can be carried out by using smart phone and commonly used software only.