Chapter 16.3, Problem 30SSC

Interpretation Introduction

Interpretation:

An experiment to determine the rate law for the general reaction $a\text{A}\text{+}b\text{B}\to \text{Products}$ needs to be explained.

Concept introduction:

One mostly used experimental method of determining order of a reaction is method of initial rates. This method determines order of a reaction by comparing initial rates of a reaction with varying concentration of reactants.

Answer to Problem 30SSC

In the method of determining order of a reaction using method of initial rates, the changes in rate due to varied concentration of reactants are observed.

Explanation of Solution

The reaction $a\text{A}\text{+}b\text{B}\to \text{Products}$, is carried out in three trials with varying concentration of A and B and their rates are to be compared. In first trial, hold the concentration of A and B constant and observe rate. To find the order of reactant A, in second trial, hold concentration of B constant and double the concentration of A and examine the effect of doubling concentration of A on reaction rate. In third trial, to find the order of B, double the concentration of B keeping the concentration of A constant. Now examine the effect of doubling the concentration of B on reaction rate

Conclusion

The relation between rate and concentration of reactants helps to determine the order of reactants.