Which combination is stated as making up acetylene production?

• A. Water and calcium carbide
• B. Nitrogen and calcium carbide
• C. Carbon dioxide and calcium carbide
• D. Oxygen and calcium carbide

Answer: (D)

Acetylene is produced by hydrolyzing calcium carbide with water. When water comes into contact with calcium carbide, it breaks down the carbide to form acetylene gas and calcium hydroxide: CaC2 + H2O → C2H2 + Ca(OH)2. The water is essential because it supplies the hydrogen that ends up in the acetylene molecule and triggers the release of C2H2 from the carbide. The other suggested combinations don’t produce acetylene in this process; for example, mixing calcium carbide with nitrogen, carbon dioxide, or oxygen does not yield acetylene in welding practice and can lead to different, non-useful or unsafe reactions. Thus, the valid pairing for acetylene production is water with calcium carbide.