Calcium carbide reacts vigorously with water to yield: 

CONCEPT:

Reaction of Calcium Carbide with Water

• Calcium carbide (CaC₂) reacts vigorously with water to produce acetylene gas (C₂H₂) and calcium hydroxide (Ca(OH)₂).
• The reaction is represented by the following chemical equation:

  CaC₂ + 2H₂O → C₂H₂ + Ca(OH)₂

EXPLANATION:

• When calcium carbide comes into contact with water, the carbide ion (C^2-) reacts with water molecules to form acetylene (C₂H₂) gas.
• Acetylene is an alkyne (hydrocarbon) characterized by a triple bond between its two carbon atoms. It is widely used as a fuel and a precursor in chemical synthesis.
• The other product of the reaction, calcium hydroxide (Ca(OH)₂), is a solid and remains in the reaction mixture.
• This reaction is highly exothermic and produces acetylene gas vigorously, which is why calcium carbide is handled with care.

Therefore, the correct answer is Option 3: Acetylene.