Assertion : The hydrolysis of methyl acetate by dil. HCl is a pseudo first order reaction
Reason : HCl acts as a catalyst for the hydrolysis .

Options

A. If both assertion and reason are true and the reason is the correct explanation of the assertion .
B. If both assertion and reason are true but reason is not the correct explanation of the assertion
C. If assertion is true but reason is false
D. If the assertion and reason both are false .

Explanation

To solve the question regarding the assertion and reason about the hydrolysis of methyl acetate by dilute HCl, we can break it down into several steps:

### Step 1: Understand the Assertion
The assertion states that the hydrolysis of methyl acetate by dilute HCl is a pseudo first-order reaction.

### Step 2: Identify the Reaction
The hydrolysis of methyl acetate (CH3COOC2H5) in the presence of water (H2O) and dilute HCl produces acetic acid (CH3COOH) and ethanol (C2H5OH). The reaction can be represented as:
\[ \text{CH}_3\text{COOC}_2\text{H}_5 + \text{H}_2\text{O} \xrightarrow{\text{HCl}} \text{CH}_3\text{COOH} + \text{C}_2\text{H}_5\text{OH} \]

### Step 3: Analyze the Reaction Order
In this reaction, both the concentration of methyl acetate and the concentration of H+ ions (from HCl) are involved. The rate law can be expressed as:
\[ R = k[\text{CH}_3\text{COOC}_2\text{H}_5][\text{H}^+] \]
This indicates that the reaction is second-order overall (first-order with respect to methyl acetate and first-order with respect to H+).

### Step 4: Establish the Pseudo First-Order Condition
Since HCl is present in excess and its concentration does not change significantly during the reaction, we can treat [H+] as a constant. Thus, we can rewrite the rate law as:
\[ R = k'[\text{CH}_3\text{COOC}_2\text{H}_5] \]
where \( k' = k[\text{H}^+] \) is a new constant. This simplification leads us to conclude that the reaction behaves as a pseudo first-order reaction with respect to the ester.

### Step 5: Understand the Reason
The reason states that HCl acts as a catalyst for the hydrolysis. This is true because HCl provides H+ ions, which facilitate the reaction without being consumed in it. Catalysts do not change their concentration during the reaction.

### Step 6: Conclusion
Both the assertion and the reason are correct. Furthermore, the reason correctly explains the assertion. Therefore, the correct option is that both the assertion and reason are true, and the reason is the correct explanation of the assertion.

### Final Answer
Both assertion and reason are true, and the reason is the correct explanation of the assertion.