The unit of reaction rate constant depends upon the

Options

A. order
B. molecularity
C. progress
D. none of these

Explanation

To determine the unit of the reaction rate constant (k), we need to analyze the relationship between the rate of reaction and the concentration of reactants. Here’s a step-by-step solution:

### Step 1: Understand the Rate of Reaction
The rate of a chemical reaction can be expressed by the equation:
\[ \text{Rate} = k [A]^n \]
where:
- \( k \) = rate constant
- \( [A] \) = concentration of the reactant
- \( n \) = order of the reaction

### Step 2: Rearranging the Equation
From the equation, we can rearrange it to express the rate constant \( k \):
\[ k = \frac{\text{Rate}}{[A]^n} \]

### Step 3: Identify Units
Now, we need to identify the units of each component:
- The unit of rate is typically expressed in terms of concentration per time, such as \( \text{mol L}^{-1} \text{s}^{-1} \).
- The unit of concentration \( [A] \) is \( \text{mol L}^{-1} \).

### Step 4: Substitute Units into the Equation
Substituting the units into the equation for \( k \):
\[ k = \frac{\text{mol L}^{-1} \text{s}^{-1}}{(\text{mol L}^{-1})^n} \]

### Step 5: Simplify the Units
This simplifies to:
\[ k = \text{mol L}^{-1} \text{s}^{-1} \cdot \text{(mol L}^{-1})^{-n} \]
\[ k = \text{mol L}^{-1} \text{s}^{-1} \cdot \text{mol}^{-n} \cdot \text{L}^n \]
\[ k = \text{mol}^{1-n} \text{L}^{n-1} \text{s}^{-1} \]

### Step 6: Conclusion
From this simplification, we can see that the units of the rate constant \( k \) depend on the order of the reaction \( n \). Therefore, the unit of the reaction rate constant depends on the **order of the reaction**.

### Final Answer
The unit of the reaction rate constant depends upon the **order of the reaction**.

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