Which of the following reagent is NOT required for the conversion...

The conversion of propyne to acetone is achieved by the hydration of an alkyne (Kucherov reaction).

The reagents used for this reaction are water, dilute $\text{H}_2\text{SO}_4$, and $\text{HgSO}_4$.

$\text{CH}_3-\text{C} \equiv \text{CH} + \text{H}_2\text{O} \xrightarrow{\text{HgSO}_4, \text{H}_2\text{SO}_4} [\text{CH}_3-\text{C(OH)}=\text{CH}_2] \rightleftharpoons \text{CH}_3-\text{CO}-\text{CH}_3$

Zinc dust is not required for this conversion. It is typically used in reactions like reductive ozonolysis or dehalogenation.

Answer: Zinc dust