Hydrolysis of ethyl acetate in acidic medium is an example of

Options

A. Unimolecular
B. Pseudo first order
C. Zero order
D. Second order

Answer

To determine the nature of the hydrolysis of ethyl acetate in acidic medium, we can analyze the reaction step by step.

### Step-by-Step Solution:

1. **Identify the Reaction**: The hydrolysis of ethyl acetate (CH3COOC2H5) in an acidic medium involves the reaction of ethyl acetate with water (H2O) in the presence of an acid (usually HCl or H2SO4).

2. **Write the Reaction Equation**:
\[ \text{CH}_3\text{COOC}_2\text{H}_5 + \text{H}_2\text{O} \xrightarrow{\text{H}^+} \text{CH}_3\text{COOH} + \text{C}_2\text{H}_5\text{OH} \]
Here, ethyl acetate reacts with water to produce acetic acid (CH3COOH) and ethanol (C2H5OH).

3. **Determine the Order of Reaction**:
- In this reaction, the concentration of water is in large excess compared to the ethyl acetate. Therefore, the concentration of water can be considered constant.
- This allows us to simplify the rate law. The rate of the reaction can be expressed as:
\[ \text{Rate} = k'[\text{CH}_3\text{COOC}_2\text{H}_5] \]
where \( k' \) is a new rate constant that incorporates the concentration of water.

4. **Identify the Molecularity**:
- The molecularity of a reaction refers to the number of reactant molecules involved in the rate-determining step. In this case, two reactants (ethyl acetate and water) are involved in the reaction.
- However, since water is in large excess, the reaction behaves as if it is first order with respect to ethyl acetate.

5. **Conclusion**:
- Since the reaction appears to be first order due to the excess of water, it is classified as a **pseudo first order reaction**. This means that although the reaction involves two reactants, the rate law simplifies to first order with respect to ethyl acetate.

### Final Answer:
The hydrolysis of ethyl acetate in acidic medium is an example of a **pseudo first order reaction**.