Greening the Clock Reaction: Rates of Reaction Lab

The amount of each reactant present and the temperature of the reaction vessel typically influence the rate at which a chemical reaction proceeds. And, typically, this relationship between the reaction rate and reagent concentration takes a simple form known as the rate law: rate = k[A]x[B]y

Clock reactions can be performed with a variety of reagents, including bisulfites, formaldehyde, mercuric ions, and thiosulfates. The traditional clock reaction involves the use of mercuric ions. While mercury compounds are typically not used in today’s classrooms, this lab provides an excellent example for highlighting how experiments have evolved and the importance of green chemistry.