A : Basic hydrolysis of ester is bimolecular in nature.
R : Acidic hydrolysis of ester is pseudo first order reaction.

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 regarding the basic and acidic hydrolysis of esters, we need to analyze both the assertion (A) and the reason (R) provided.

### Step 1: Analyze the Assertion (A)
The assertion states that "Basic hydrolysis of ester is bimolecular in nature."

- **Explanation**: Basic hydrolysis of esters involves the reaction of an ester with a base (like NaOH). The reaction can be represented as follows:

\[ \text{RCOOR'} + \text{OH}^- \rightarrow \text{RCOO}^- + \text{R'OH} \]

In this reaction, both the ester and the hydroxide ion (OH⁻) are involved in the rate-determining step. The rate of the reaction can be expressed as:

\[ \text{Rate} = k[\text{RCOOR'}][\text{OH}^-] \]

Since the rate depends on the concentrations of both the ester and the hydroxide ion, the reaction is bimolecular. Therefore, the assertion is **true**.

### Step 2: Analyze the Reason (R)
The reason states that "Acidic hydrolysis of ester is a pseudo first-order reaction."

- **Explanation**: Acidic hydrolysis of esters involves the reaction of an ester with water in the presence of an acid (H⁺). The reaction can be represented as:

\[ \text{RCOOR'} + \text{H}_2\text{O} \xrightarrow{\text{H}^+} \text{RCOOH} + \text{R'OH} \]

In this case, water is in large excess and can be considered a solvent. The rate law for this reaction can be expressed as:

\[ \text{Rate} = k[\text{RCOOR'}] \]

Since the concentration of water remains constant (acting as a pure solvent), it does not appear in the rate expression. Thus, the reaction behaves as if it is first-order with respect to the ester, making it a pseudo first-order reaction. Therefore, the reason is also **true**.

### Step 3: Determine the Relationship Between A and R
Now we need to determine if the reason correctly explains the assertion.

- The assertion is about the nature of basic hydrolysis being bimolecular, while the reason discusses acidic hydrolysis being pseudo first-order. Although both statements are true, they do not explain each other or relate directly.

### Conclusion
Since both the assertion and the reason are true but the reason does not explain the assertion, the correct answer is:

**Option 2**: Both assertion and reason are true, but the reason is not the correct explanation of the assertion.

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