The role of a catalyst in a reversble reaction is to

Options

A. Increase the rate of forward reaction
B. Decrease the rate of backward reaction
C. Alter the equilibrium constant of a reaction
D. Allow the equilibrium to be achieved quickly

Answer

### Step-by-Step Solution:

1. **Understanding Reversible Reactions**:
- A reversible reaction is one where the products can react to form the original reactants. This means that both the forward and reverse reactions occur simultaneously, and the system can reach a state of equilibrium.

2. **Defining a Catalyst**:
- A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process. It provides an alternative pathway for the reaction with a lower activation energy.

3. **Role of a Catalyst in Reversible Reactions**:
- In reversible reactions, a catalyst speeds up both the forward and reverse reactions equally. This means that it does not favor one direction over the other but helps the system reach equilibrium faster.

4. **Effect on Equilibrium Constant**:
- Importantly, a catalyst does not change the position of the equilibrium or the equilibrium constant. It only helps the system achieve equilibrium more quickly.

5. **Conclusion**:
- Therefore, the correct role of a catalyst in a reversible reaction is to allow the equilibrium to be achieved quickly.

### Final Answer:
The role of a catalyst in a reversible reaction is to **allow the equilibrium to be achieved quickly**.

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