A catalyst

Options

A. increase the free energy change of the reaction
B. decreases the free energy change of the reaction
C. neither increases nor decreases the free energy of the reaction
D. may increases or decrease depending upon the nature of the catalyst

Explanation

**Step-by-Step Solution:**

1. **Definition of a Catalyst**: A catalyst is a substance that increases the rate of a chemical reaction without undergoing any permanent chemical change itself.

2. **Mechanism of Action**: The primary way a catalyst accelerates a reaction is by lowering the activation energy (Ea). Activation energy is the minimum energy required for a reaction to occur.

3. **Impact on Reaction Rate**: By lowering the activation energy, a catalyst allows more reactant molecules to have sufficient energy to overcome this barrier, thereby increasing the number of successful collisions per unit time. This results in an increased reaction rate.

4. **Kinetic vs. Thermodynamic Factors**: It is important to note that while a catalyst affects the kinetic aspect of a reaction (the rate), it does not alter the thermodynamic properties of the reaction, such as the change in free energy (ΔG). The overall energy change of the reaction remains the same, regardless of the presence of a catalyst.

5. **Conclusion**: In summary, a catalyst speeds up a reaction by lowering the activation energy required for the reaction to proceed, thereby increasing the reaction rate without affecting the overall thermodynamic properties of the reaction.

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