Alkyne  →dil.  H2SO4H2O,   Hg+2   X.  ‘X’  in this reaction cannot be

Alkynes on  acidic hydration always follow markonikoff’s addition. The negative part –OH  group always attacks the non-terminal carbon. On tautomerism ketone is formed, but not   an  aldehyde. Only Ethyne (which has only terminal carbons) gives Ethanal (Aldehyde).