The correct option is Hydrogen.
Explanation
The reaction between alcohols and active metals demonstrates the acidic nature of alcohols, specifically involving the cleavage of the oxygen-hydrogen (O-H) bond.
When metallic sodium reacts with ethanol (ethyl alcohol), it acts as a base and displaces the hydrogen atom from the hydroxyl (-OH) group of the ethanol molecule. This displacement results in the formation of sodium ethoxide and the liberation of hydrogen gas. This reaction is commonly used as a test to detect the presence of the hydroxyl group in organic compounds.
The chemical equation for this reaction is:
2C2H5OH + 2Na → 2C2H5ONa + H2 ↑
(Ethanol) + (Sodium) → (Sodium Ethoxide) + (Hydrogen)
Key Takeaway: Active metals such as sodium and potassium react with alcohols to form metal alkoxides and evolve hydrogen gas.