A : Hydrolysis of ester in acidic medium follows first order kinetics.
R : Hydrolysis of ester is independent of the concentration of acid used.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion , then mark (1).
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion , then mark (2).
C. If Assertion is true statement but Reason is false, then mark (3).
D. If both Assertion and Reason are false statements , then mark (4)

Answer

To solve the question, we need to analyze the assertion and reason provided:

**Assertion (A)**: Hydrolysis of ester in acidic medium follows first order kinetics.
**Reason (R)**: Hydrolysis of ester is independent of the concentration of acid used.

### Step-by-Step Solution:

1. **Understanding Hydrolysis of Ester**:
- The hydrolysis of an ester, such as ethyl acetate (CH3COOC2H5), in an acidic medium produces acetic acid (CH3COOH) and ethanol (C2H5OH).

2. **Rate Expression**:
- The general rate expression for a reaction involving an ester and water can be written as:
\[ \text{Rate} = k \cdot [\text{Ester}] \cdot [\text{H}_2\text{O}] \]
- Here, \( k \) is the rate constant, and \([Ester]\) and \([H_2O]\) are the concentrations of the ester and water, respectively.

3. **Excess Water**:
- In hydrolysis reactions, water is typically used in excess. This means that the concentration of water remains relatively constant throughout the reaction.

4. **Simplifying the Rate Expression**:
- Since water is in excess, we can treat its concentration as a constant. Thus, we can express the rate as:
\[ \text{Rate} = k' \cdot [\text{Ester}] \]
- Here, \( k' = k \cdot [H_2O] \) is a new constant that incorporates the concentration of water.

5. **Determining the Order of Reaction**:
- The simplified rate expression shows that the rate of reaction depends only on the concentration of the ester. This indicates that the reaction is first order with respect to the ester.

6. **Evaluating the Assertion**:
- Since the hydrolysis of the ester follows first order kinetics, the assertion (A) is **true**.

7. **Evaluating the Reason**:
- The reason states that the hydrolysis of ester is independent of the concentration of acid used. Since the rate of reaction is only dependent on the concentration of the ester (and not on the acid or water), this statement is also **true**.

8. **Conclusion**:
- Both the assertion and reason are true, and the reason correctly explains the assertion. Therefore, the correct option is that both statements are true, and the reason is the correct explanation of the assertion.

### Final Answer:
The correct option is **Option 1**: Both assertion and reason are true, and the reason is the correct explanation of the assertion.

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