Final answer:
The final product when an alkyne is treated with H2O, H2SO4, in the presence of HgSO4, is a ketone, resulting from the hydration of the alkyne through a process involving a mercurinium ion intermediate and tautomerization of an enol to a ketone.
Step-by-step explanation:
When an alkyne is treated with H2O (water), H2SO4 (sulfuric acid), in the presence of HgSO4 (mercury(II) sulfate), the reaction that occurs is known as hydration. The final product of this reaction is a ketone. During this process, the alkyne undergoes an addition reaction where water adds across the carbon-carbon triple bond. This reaction proceeds through a mercurinium ion intermediate and results in the formation of an enol, which quickly tautomerizes to a ketone. Sulfuric acid is used as a catalyst to facilitate the hydration while HgSO4 ensures Markovnikov addition, where water adds to the carbon with the greatest number of hydrogen atoms.
It’s important to note that an HOH molecule does not get eliminated and an alkene is not formed in this case, indicating a possible confusion in the provided reference information. Instead, the alkyne is transformed directly into a ketone without the intermediate formation of an alkene. Furthermore, the product formation does not depend on which adjacent carbon loses the H atom as this pertains to an alkene mechanism, not the alkyne hydration under these conditions.