Hydrolysis of Propyne in the presence of HCl and HgSO4

The hydrolysis of propyne in the presence of HCl and HgSO4 is an acid-catalyzed reaction that involves the addition of water to the triple bond of propyne. This reaction is known as hydration and leads to the formation of a ketone as the major product.

The Mechanism of the Reaction:
1. Protonation of the triple bond: In the presence of HCl, the triple bond of propyne is protonated to form a resonance-stabilized carbocation intermediate. This step is the slowest step of the reaction.

2. Nucleophilic attack by water: The positively charged carbon atom in the carbocation intermediate is highly reactive and is attacked by a water molecule acting as a nucleophile. The water molecule donates a pair of electrons to form a bond with the carbon atom, leading to the formation of a secondary carbocation intermediate.

3. Deprotonation: In the presence of excess water, the secondary carbocation intermediate is deprotonated by water acting as a base. The proton is transferred from the carbon atom to a water molecule, resulting in the formation of the final product.

Formation of Acetone:
In the case of propyne, the final product obtained after hydrolysis is acetone (CH3COCH3). This is because the secondary carbocation intermediate can undergo resonance stabilization with the carbonyl group of the ketone, resulting in the formation of an energetically favorable product.

The resonance stabilization occurs due to the donation of electron density from the oxygen of the carbonyl group to the positively charged carbon atom, which helps in stabilizing the positive charge.

Conclusion:
The hydrolysis of propyne in the presence of HCl and HgSO4 leads to the formation of acetone as the major product. This reaction involves the addition of water to the triple bond of propyne, followed by the formation of a carbocation intermediate and subsequent deprotonation. The resonance stabilization of the intermediate leads to the formation of acetone as the final product.