Consider a reaction that occurs by the following mechanism:

A + BC → AC + B

AC + D → A + CD

The potential energy profile for this reaction is as follows:

(b) Write structural formulas for all species present at reaction stages 1–5. Identify each species as a reactant, product, catalyst, intermediate, or transition state.

Video transcript

Hello everyone today. We have the following problem. A certain reaction involves the following two step reaction mechanism. The energy diagram for the reaction is shown below. What are these structural formulas of the species present from points? I 2.125 indicate the type or role of each species. So we have this following chemical reaction here. We need to find out what the overall reaction will be. So we're just gonna right over here. The overall reaction, it's going to take into account any catalysts or intermediates. So a catalyst is something that is started in the first step and regenerated at the end for the second step. So that's going to be our end right here. So we can go and cross that out. We can go in and cross out an intermediate which is not a final product. And so that's going to be N. M. And M. As well. And so the overall reaction is going to be L M plus oh it's going to give us L plus M. O. That's the overall reaction here. So at the start of the reaction or at I this is going to be simply where we only have the reactions present. So at I that is where the reaction starts at one that is going to be over there where the reactant are present. And the reactions are we're going to have L that's bonded to the M. And then we're going to have the oh there and these are going to be our reactant. And so what about the nitrogen that is there in the first step. Well, as you said before, nitrogen gets crossed out because it is used in the first step and regenerated in the second step. So we can say that in is going to be our catalyst. Now, if you look at two, two is out of position, the maxima of a peak and the maximum is going to be the transition state. And the transition state is simply where the products or where the bonds are forming and breaking of various compounds or elements. That's going to be representative by the L. We're gonna draw this in dots breaking from the M. And the M. Is joining bonds with the N. And so this is going to be our transition state. And of course we do have that O. And that O. Is simply going to be our reactant. Moving on to three. This is a dip into the graph here and the dip is represented by an intermediate. So it's the second step with the intermediate. And so we already identified the intermediate to be the M. With the in and so this is going to be our intermediate. And then we're gonna say that we're going to have a product which is L. And we're also gonna have our reactant which is the. Oh so notice how the O. Is always present in this throughout this, if we look at four here, that's another maxima, that's gonna be a secondary transition state. And that's going to be the bond from in breaking from in and the m joining with the O. And that's gonna be our second transition state. And of course we have the L. And the L. Is going to be our product. Now. We look at five, which is our last and final step and the last and final step. You're just simply going to have the products and the catalyst. And so the product is going to be our M. Bonded to R. O. Plus the L. These are gonna be our products and then you're gonna have in as the catalyst and this is our breakdown of each species at different steps of this process and what they are overall. I hope this helped ahead until next time.