The term mechanism describes the series of steps by which an overall reaction occurs. The study of mechanisms of chemical reactions is one of the most obvious cases in science of the formation of an hypothesis, gathering of evidence, testing of tentative conclusions, positing of a theory and revision when new data are brought to light - an important illustration of the way science works. Chemists who attempt to deduce mechanisms, just as those who study chemical structures or equilibria, must be willing to give up their cherished conclusions when new, reliable data are presented.

From many studies, some important classes of mechanisms have been deduced. These serve as a guide for kineticists and provide us with insight about how reactions occur. Many "simple" reactions actually occur by one of these multi-step mechanisms.

Rate Determining Step

If an overall reaction consists of several steps, it is...