The acid hydrolysis of ester is: (i) first order reaction (ii) bimolecular reaction (iii) unimolecular reaction (iv) second order reaction The true statements are

Options

A. I,ii
B. All are correct
C. ii,iv
D. ii,iii,iv

Explanation

To determine the correct statements regarding the acid hydrolysis of an ester, let's analyze the reaction step by step:

### Step 1: Understanding the Reaction
The acid hydrolysis of an ester involves the reaction of the ester with water in the presence of an acid catalyst. For example, if we take ethyl acetate (CH3COOCH2CH3) as the ester, the reaction can be represented as:
\[ \text{CH}_3\text{COOCH}_2\text{CH}_3 + \text{H}_2\text{O} \xrightarrow{\text{H}^+} \text{CH}_3\text{COOH} + \text{C}_2\text{H}_5\text{OH} \]
This reaction produces acetic acid and ethanol.

### Step 2: Determining the Rate Law
In this reaction, water is present in large excess. Therefore, its concentration does not significantly change during the reaction, allowing us to treat it as a constant. The rate law can be expressed as:
\[ \text{Rate} = k' [\text{Ester}] \]
where \( k' \) is the pseudo-first-order rate constant. This indicates that the reaction is first-order with respect to the ester.

### Step 3: Order of the Reaction
Since the rate of the reaction depends only on the concentration of the ester and not on the concentration of water, we classify this reaction as a first-order reaction.

### Step 4: Molecularity of the Reaction
Molecularity refers to the number of reactant molecules that are involved in the rate-determining step of the reaction. In this case, two molecules are involved: one ester molecule and one water molecule. Therefore, the molecularity of this reaction is bimolecular.

### Conclusion
Based on the analysis:
- The reaction is **first-order** with respect to the ester (due to the pseudo-first-order condition).
- The reaction is **bimolecular** because it involves two reactant molecules.

Thus, the correct statements regarding the acid hydrolysis of an ester are:
- (i) First order reaction: **True**
- (ii) Bimolecular reaction: **True**
- (iii) Unimolecular reaction: **False**
- (iv) Second order reaction: **False**

### Final Answer
The true statements are (i) and (ii).

---