Which one of the following is the intermediate in the preparation of a ketone by hydration of an alk

Question

Which one of the following is the intermediate in the preparation of a ketone by hydration of an alkyne in the presence of sulfuric acid and mercury (II) sulphate ?

Professor PC Thomas Classes · Answer

Reaction proceed through enol format on and $\mathrm{H}_2 \mathrm{O}$ attack on stable (d) carbocation in this reaction.
$	herefore \quad(\mathrm{d})$ is most favourable. (Kucherov reaction)