Question

Consider the following representation of a reaction mechanism.

Step 1: Unimolecular (fast)
Step 2: Bimolecular (slow)
Step 3: Unimolecular (fast)
Which conclusion about the rate law for the reaction above is reasonable?
A. It is first order overall because step 1 is unimolecular.
B. It is first order overall because both steps 1 and 3 are unimolecular.
C. It is second order overall because step 2 is bimolecular.

Answer 1

The correct answer is: D. It is second order overall because step 2 is bimolecular.

Answer 2

The rate determining step would be the slow step. Thus, Step 2 which is bimolecular is the rate determining step. I believe the correct answer from the choices listed above is option C. The reasonable conclusion would be that it is second order overall because step 2 is bimolecular. Hope this answers the question.