Chapter 22, Problem 22.1P

Interpretation Introduction

Interpretation:

The rate of the overall reaction is to be determined.

Concept introduction:

Reaction rate is defined as the speed at which a chemical reaction proceeds. It is often expressed in terms of either the concentration (amount per unit volume) of a product that is formed in a unit of time or the concentration of a reactant that is consumed in a unit of time.

The order of reaction is nothing but the power of concentration of each reactant. Therefore, the rate of first order reaction depends on concentration of single species.

Answer to Problem 22.1P

The reaction will be 6 times faster.

Explanation of Solution

The rate law for reaction is $\text{R=k}\left[{\text{E}}^{\text{+}}\right]\left[\text{Benzene}\right]\text{.}$

The general electrophilic aromatic substitution reaction is first order with respect to the concentration of benzene and first order with respect to the concentration of the electrophile. So, when we triple the concentration of benzene, it triples the reaction rate. Also, when we double the concentration of electrophile, it doubles the reaction rate. Therefore, the reaction rate will be six times faster.

$\text{Rate = k}\left[{\text{ 2 x E}}^{\text{+}}\right]\left[\text{ 3 x Benzene}\right]\to \text{6 x rate }$

Conclusion

The given rate is determined by applying the concepts of Electrophilic Aromatic Substitutions and rate laws.