Can a catalyst be present in the rate equation?
Yes, a catalyst can be included in a rate law. That’s because, most reactions occur in a series of step and the rate is based on the “rate determining step”, which is the slowest step. A catalyst may be a reactant in the rate determining step, and a product in a subsequent step. Therefore, the catalyst is not included in the overall reaction. But a catalyst need not always be in the rate law. The rate law is usually based on the rate determining step. ========== Follow up =========== In the free response questions on the AP chemistry exam there has been at least one case where a rate law included a catalyst( 2002D). Brown and LeMay always include at least one in their examples, and I always cover this situation when I teach rate laws and mechanisms in AP chemistry. Here is one comment: “Other examples of species not in the balanced reaction occurring in the rate law would include catalysis, where a catalyst does not normally appear in the balanced reaction but does appear in the rate l
