But -1- yne and but -2- yne are treated with dil . `H_(2) SO_(4) ` in presence of `HgSO_(4)` at 330 K.

Explanation

Addition of `H_(2)O` occurs to form butan -2- one in each case
`CH_(3)CH_(2) -C-= CH+H_(2)O overset(Dil. H_(2)SO_(4) ,HgSO_(4))underset(330K)(to) [CH_(3) CH_(2)-underset(OH)underset(|)(C)=CH_(2)] overset("Tautomerises ")(to)`
`underset("Butan-2-one ")(CH_(3)CH_(2)-overset(O)overset(||)(C)-CH_(3))`
`underset("But-2-yne")(CH_(3)-C-=C-CH_(3)+H_(2)O) overset(Dil. H_(2)SO_(4) ,HgSO_(4))underset(330K)(to) [CH_(3)-underset(OH)underset(|)(C)=CHCH_(3)] overset("Tautomerises")(to)`
`underset("Butan -2-one ")(CH_(3) -underset(O)underset(||)(C)-CH_(2)CH_(3))`