Question

A reaction having equal energies of activation for forward and reverse reactions has

• A. ΔS = 0
• B. ΔG = 0
• C. ΔH = 0
• D. ΔH = ΔG = ΔS = 0

Answer 1

The Correct Option is C

To answer the question about the reaction having equal energies of activation for both the forward and reverse reactions, we need to delve into the concepts of thermodynamics and chemical kinetics.

In any chemical reaction, the \Delta H\, (enthalpy \, change) can be related to the energies of activation of the forward and reverse reactions. The energy of activation is the minimum energy required for a reaction to proceed.

If the energies of activation for the forward and reverse reactions are equal, it indicates a specific scenario where there is no net change in enthalpy as the reaction proceeds. This is because the energy barrier to proceeding in either direction is the same.

Let's analyze the given options to clearly understands why \Delta H = 0 is correct:

• ΔS = 0: Entropy change describes the randomness or disorder of the system. Equal activation energies do not necessarily mean there is no change in entropy.
• ΔG = 0: Gibbs free energy change being zero would imply that the reaction is at equilibrium. However, equal activation energies do not definitively point to zero gibbs free energy.
• ΔH = 0: Equal energies of activation imply the enthalpy change in transitioning from reactants to products and vice-versa is zero, since there is no energy gained or lost in the process.
• ΔH = ΔG = ΔS = 0: While the enthalpy change is zero, it does not automatically indicate zero ΔG or ΔS without further context.

Conclusion: The correct answer is ΔH = 0, implying there is no net enthalpy change in the reaction under the given conditions.