`Ph - C -= C-CH_(3) overset(Hg^(2+)//H_(2)SO_(4)(aq)) to A`
The major product (A) formed is -

Options

A.
B.
C.
D.

Answer

To solve the problem, we need to determine the major product (A) formed when the compound `Ph - C ≡ C - CH3` reacts with `Hg^(2+)` in the presence of `H2SO4 (aq)`. This reaction involves the hydration of an alkyne, and we will apply Markovnikov's rule to find the major product.

### Step-by-Step Solution:

1. **Identify the Reactant**:
The reactant is `Ph - C ≡ C - CH3`, which is an alkyne with a phenyl group (Ph) and a methyl group (CH3) attached to the carbon atoms of the triple bond.

2. **Understand the Reaction Conditions**:
The reaction is carried out in the presence of `Hg^(2+)` and `H2SO4`. This indicates that we will be performing a hydration reaction where water (H2O) will add across the triple bond.

3. **Apply Markovnikov's Rule**:
According to Markovnikov's rule, when adding a reagent to an unsymmetrical alkene or alkyne, the negative part of the reagent will attach to the carbon atom with fewer hydrogen atoms. In this case:
- The carbon atom attached to the phenyl group (Ph) has fewer hydrogen atoms compared to the carbon attached to the methyl group (CH3).
- Therefore, the hydroxyl group (OH) from water will add to the carbon that is part of the phenyl group, and the hydrogen (H) will add to the carbon attached to the methyl group.

4. **Draw the Product After Hydration**:
After applying Markovnikov's rule, the product formed will be:
- `Ph - C(OH) = C(H) - CH3`
This product is an enol because it contains a hydroxyl group (-OH) and a double bond.

5. **Tautomerization**:
The enol form can undergo tautomerization to form a more stable keto form. In this case, the enol will rearrange to form a ketone:
- The enol `Ph - C(OH) = C(H) - CH3` will convert to the keto form `Ph - C(=O) - CH2 - CH3`.

6. **Final Product**:
The major product (A) after tautomerization is:
- `Ph - C(=O) - CH2 - CH3`, which is a ketone.

### Conclusion:
The major product (A) formed from the reaction is a ketone with the structure `Ph - C(=O) - CH2 - CH3`.