Chapter 16, Problem 70A

Interpretation Introduction

Interpretation:

To determine which step in the reaction mechanism is the rate determining step.

Concept introduction:

In chemical kinetics, the slowest step is used for the determination of the overall rate of a reaction and it is often termed as the rate determining step of the reaction.

Answer to Problem 70A

Step 2 is the rate determining step.

Explanation of Solution

The slowest step is the rate determining step in a complex reaction which is composed of two or more than two intermediate steps.

Given two steps,

$\begin{array}{l}\text{Step}\text{1:}\left(\text{fast}\right)\text{A+}\text{B}\to \text{C}\\ \text{Step}\text{2:}\left(\text{slow}\right)\text{C+}\text{D}\to \text{E}\end{array}$

Step 2 is the rate determining step out of the two given steps because is the slower elementary step.

Conclusion

Step 2 is the rate determining step because is the slower elementary step.