The rate of the reaction A + B2 S AB + B is directly proportional...

Question

The rate of the reaction A + B2 S AB + B is directly proportional 
to the concentration of B2, independent of the 
concentration of A, and directly proportional to the concentration 
of a substance C. 
(c) What is the role of C in this reaction? Why doesn't C 
appear in the chemical equation for the overall reaction?

Accepted Answer

Hello everyone today. We have the following problem. The rate of the decomposition of hydrogen peroxide is directly proportional to the concentration of peroxide and platinum. And then we have the rate equation here shown below is the reaction mechanism explain why platinum is in the rate law but is not in the overall chemical equation. Well, first let's examine his answer choices. So if you look at answer choice A. It says platinum is in the right law because it causes the reaction to slow down so that the reaction can be observed, but the reaction can proceed rapidly without it. So this is actually incorrect. And so why is option a incorrect? This is because platinum does not slow down the reaction, but it actually increases it. So platinum increases the rate of a reaction and why is that? That is because it is a catalyst. So it will not slow the reaction down. This beast has platinum is used in large amounts. But it is involved in an elementary step. That is too slow to be significant for the overall equation. We'll answer choice B is actually incorrect as well because the information regarding the amount of platinum was not given. And the presence of platinum in the slow or rate determining step meant that it's it is significant in the reaction. So this is our rate determining step here. And so the fact that platinum was present means that it is significant, moreover, the amount was not specified. The amount of platinum was not specified. And if you look at answer choice C planning can be ignored in the overall chemical equation. Even if it is part of the slow step, because it is used in small quantities. Once again, this is going to be incorrect because the amount of platinum was not specified and thus that leaves anti choice D is the correct answer. Platinum is in the rate law because it is in a really reacted in the slow or rate determining step and is not in the overall chemical equation because it is a catalyst. The platinum catalyst is consumed in the first step and regenerated in the final step. And we can see here that are platinum rate right here is in the first step and is regenerated in our second step or the last step. And so with that we've answered the question overall Help. This helped and until next time.

Watch next