Chapter 22, Problem 1P

Which of the following parameters would be different for a reaction carried out in the presence of a catalyst, compared with the same reaction carried out in the absence of a catalyst? (Hint: See Section 5.13.)

ΔG°, ΔH°, E_a, ΔS^z, ΔH°, K_eq. ΔG^z, ΔS°, K_rate

Interpretation Introduction

Interpretation: The parameters those are different for a reaction taking place in the presence of a catalyst compared with the same reaction taking place in the absence of a catalyst has to be identified.

Concept introduction:

Catalyst: Substance which helps in increasing the rate of a particular reaction without getting consumed in the reaction. It does not get consumed or changed by the reaction. It provides a different pathway where the transition state is more stable and with shorter energy hill.

Explanation of Solution

Catalyst provides a different pathway where the transition state is more stable and with shorter energy hill.  Energy difference of the rate-determining step taking place between the reactant and transition state is reduced by a catalyst and increases the rate of the reaction.  Hence the height of energy hill is decreased in this step.  The parameters that depend on the energy difference of the rate-determining step taking place between the reactant and transition state differ while the reaction occurs in presence of a catalyst.  Therefore, the parameters those are different for a reaction taking place in the presence of a catalyst compared with the same reaction taking place in the absence of a catalyst are $\Delta H^{\ne },E_a,\Delta S^{\ne },\Delta G^{\ne },k_{rate}$.  The other parameters are not affected by the energy difference of the rate-determining step taking place between the reactant and transition state.

Conclusion

The parameters those are different for a reaction taking place in the presence of a catalyst compared with the same reaction taking place in the absence of a catalyst were identified as $\Delta H^{\ne },E_a,\Delta S^{\ne },\Delta G^{\ne },k_{rate}$.