On which of the following factors, the rate constant does not depend?

Options

A. Temperature
B. Concentration
C. Presence of catalyst
D. Nature of reactants

Explanation

To determine the factor on which the rate constant does not depend, we can analyze the factors affecting the rate constant (K) in a chemical reaction. Here’s a step-by-step solution:

### Step 1: Understand the Rate Constant
The rate constant (K) is a proportionality factor in the rate equation of a chemical reaction. It relates the rate of reaction to the concentrations of the reactants.

### Step 2: Identify Factors Affecting the Rate Constant
The rate constant is influenced by several factors:
- **Temperature**: The rate constant increases with an increase in temperature.
- **Catalysts**: The presence of a catalyst can increase the rate constant by providing an alternative pathway for the reaction.
- **Surface Area of Solid Reactants**: For reactions involving solids, an increase in surface area can lead to an increase in the rate constant.
- **Nature of Reactants**: Different reactants can have different rate constants due to their intrinsic properties.

### Step 3: Identify the Factor that Does Not Affect the Rate Constant
Among the factors listed above, the rate constant does NOT depend on the concentration of the reactants. While the rate of reaction is affected by the concentration, the rate constant itself remains unchanged by changes in concentration.

### Conclusion
Therefore, the rate constant does not depend on the concentration of the reactants.

### Final Answer
The rate constant does not depend on the concentration of the reactants.

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