Chapter 16, Problem 71A

Interpretation Introduction

Interpretation:

The steps 1 and 2 in the reaction described in previous problem needs to be determined. Also, the substance C needs to be determined.

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 71A

Step 1 and 2 are called elementary steps and substance C is called as an intermediate.

Explanation of Solution

Given two steps,

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

This is a complex reaction as it consists of two elementary steps. Step 1 and 2 are hence called as elementary steps.

In step 1, substance C forms and then same substance C is consumed in step 2. C does not appear in the final product of the complex reaction.

Therefore, C is an intermediate.

Conclusion

The given reaction is a complex reaction so Step 1 and 2 are its elementary steps and C is the intermediate.