Concept:The direct catalytic hydration (addition of water) to a hydrocarbon yields a carbonyl compound only if the hydrocarbon is an alkyne.
Formula:$$ H-C \equiv C-H + H_2O \xrightarrow{HgSO_4 / H_2SO_4} [CH_2=CH-OH] \rightleftharpoons CH_3-CHO $$
Solution:- When alkynes are hydrated using mercuric sulfate and sulfuric acid, they form unstable enol intermediates.
- These enols rapidly undergo tautomerization to form stable aldehydes or ketones.
- The general formula for an alkyne (containing one triple bond) is \( C_nH_{2n-2} \).
Why other options are incorrect:Option A (\( C_nH_{2n+2} \)) is an alkane, which does not undergo hydration. Option B (\( C_nH_{2n} \)) is an alkene, which yields an alcohol upon hydration, not a carbonyl compound.
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