J.R. S. answered 10/09/20
Ph.D. University Professor with 10+ years Tutoring Experience
Crystal violet is relatively stable in the absence of hydroxide. When in the presence of hydroxide (OH-), it forms a complex and the color changes from a transparent blue to a colorless solution.
Know the rate law is important if you want to study or learn about the kinetics of the reaction. It allows you to calculate the rate constant and the order of the reaction with respect to each reactant.