Determining a catalyst

[Ellie_Keenan_2A]

Does a catalyst always have to be present in the first step of a reaction? Or does it just need to be present in the reactants of one of the steps?

[205975909]

A catalyst does not necessarily have to be present in the first step of a reaction. It can be present in any step, either as a reactant or a product, as long as it participates in the reaction mechanism and facilitates the conversion of reactants to products without being consumed itself.

[Jolene Robles 2H]

No, a catalyst does not need to be in the first step of a reaction occur. A catalyst speeds up the reaction which can happen anytime so a catalyst does not necessarily need to happen at the beginning. In the end the catalyst will do what it is needed to do which is lower the energy barrier no what what step it takes place it.