The value of the rate constant of a pseudo first order reaction ……… .

Options

A.  depends on the concentration of reactants present in small amount
B. depends on the concentration of reactants present in excess
C. is independent of the concentration of reactants
D.  depends only on temperature

Explanation

To solve the question regarding the value of the rate constant of a pseudo first-order reaction, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Pseudo First-Order Reactions**:
- Pseudo first-order reactions are those where the rate of reaction appears to depend on the concentration of only one reactant, while the other reactant is in excess. This means that the concentration of the excess reactant does not affect the rate of the reaction.

2. **Identify the Reaction**:
- An example of a pseudo first-order reaction is the hydrolysis of ethyl acetate (CH₃COOC₂H₅) in the presence of excess water (H₂O). The reaction can be written as:
\[ \text{CH}_3\text{COOC}_2\text{H}_5 + \text{H}_2\text{O} \rightarrow \text{CH}_3\text{COOH} + \text{C}_2\text{H}_5\text{OH} \]

3. **Rate Expression**:
- The rate of the reaction can be expressed as:
\[ \text{Rate} = k[\text{CH}_3\text{COOC}_2\text{H}_5]^1[\text{H}_2\text{O}]^0 \]
- Here, since water is in excess, its concentration remains relatively constant and does not affect the rate. Therefore, it is raised to the power of zero.

4. **Determine Dependence of Rate Constant**:
- The rate constant \( k \) for a pseudo first-order reaction depends on the concentration of the reactant that is not in excess (in this case, ethyl acetate) and is also influenced by temperature. However, it does not depend on the concentration of the reactant present in excess (water).

5. **Conclusion**:
- From the options given, the correct answer is that the value of the rate constant of a pseudo first-order reaction depends on the concentration of the reactant present in small amounts (ethyl acetate), and it is independent of the concentration of the reactant present in excess (water).

### Final Answer:
The value of the rate constant of a pseudo first-order reaction depends on the concentration of the reactant present in small amounts.