In the following reaction, What is X ?

Acetylene on hydration reaction with 4 2 4 / HgSO H SO gives oxymercuration reaction by following the Markownikoff’s rule. As per this rule, hydronium ion goes to the carbon bearing more number of hydrogens. Consequently, the negative part goes to the carbon bearing lesser number of hydrogens. In the second step enol is formed, which tautomerizes to give acetaldehyde as product. 2 4 4 2 3 | dil.H SO Tautomerism HgSO HC CH HC=CH CH CHO OH -> ->