Alkynes react with water in the presence of dilute sulphuric acid and mercuric sulphate at $333\text{ K}$ to undergo a hydration reaction . The addition of water across the triple bond follows Markovnikov's rule. For phenylacetylene ($\text{C}_6\text{H}_5\text{-C}\equiv\text{CH}$), this hydration initially yields an unstable enol intermediate ($\text{C}_6\text{H}_5\text{-C(OH)=CH}_2$), which rapidly undergoes tautomerisation to form the more stable ketone product, acetophenone ($\text{C}_6\text{H}_5\text{COCH}_3$).

Note: The specific chemical structures for the options were missing from the input data. Option 1 is marked correct based on the provided probable answer.