`CH_(3)-overset(O)overset(||)(C)-overset(16)(O)-H+R-overset(18)(O)-Hoverset("dil." H_(2)SO_(4))underset(Delta)to`
Major product.
Product of the reaction is

Options

A. `CH_(3)-overset(O)overset(||)(C)-overset(18)(O)-R`
B. `CH_(3)-overset(O)overset(||)(C)-overset(16)(O)-R`
C. `R-overset(O)overset(||)(C)-overset(18)(O)-CH_(3)`
D. `R-underset(O)underset(||)(C)-underset(16)(O)-R`

Answer

To solve the question regarding the reaction of a compound with carboxylic acid and alcohol in the presence of dilute H₂SO₄, we will follow these steps:

### Step 1: Identify the Reactants
The reactants given are:
- A compound with the structure CH₃-CO-CHO (which is an aldehyde)
- An alcohol (ROH) with a molecular weight of 18 (which indicates it is likely ethanol, C₂H₅OH)
- Dilute H₂SO₄, which acts as an acid catalyst.

### Step 2: Protonation of the Carbonyl Oxygen
When the dilute sulfuric acid (H₂SO₄) is added, it donates a proton (H⁺) to the carbonyl oxygen of the aldehyde. This increases the electrophilicity of the carbonyl carbon, making it more susceptible to nucleophilic attack.

### Step 3: Nucleophilic Attack by Alcohol
The lone pair of electrons on the alcohol (ROH) attacks the electrophilic carbonyl carbon. This results in the formation of a tetrahedral intermediate. The structure at this stage can be represented as:
- CH₃-C(OH)(OR)-OH

### Step 4: Rearrangement and Elimination of Water
In the tetrahedral intermediate, the hydroxyl group (OH) can lead to the formation of a more stable product. Since two hydroxyl groups on one carbon are not stable, a water molecule (H₂O) is eliminated. This results in the formation of a carbonyl compound.

### Step 5: Final Product Formation
After the elimination of water, the final product will be a compound with the structure:
- CH₃-C(=O)-OR
Where OR represents the alkoxy group from the alcohol (which is derived from the alcohol used in the reaction).

### Step 6: Identify the Major Product
Since the alcohol used has a molecular weight of 18 (which corresponds to ethanol), the final product will be:
- CH₃-C(=O)-O-C₂H₅ (where C₂H₅ is the ethyl group from ethanol).

Thus, the major product of the reaction is:
- **CH₃-CO-O-C₂H₅**

### Summary of the Reaction
The reaction can be summarized as follows:
1. Protonation of the carbonyl oxygen.
2. Nucleophilic attack by the alcohol.
3. Formation of a tetrahedral intermediate.
4. Elimination of water to form the final ester product.