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How does calcium carbide produce acetylene gas?

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A labeled diagram of the periodic table entry for calcium, showing its atomic number 20, symbol Ca, atomic weight 40.078, electron configuration, and classification as an alkaline-earth metal. Icons indicate calcium is a solid with a face-centered cubic crystal structure and strongly basic oxides at room temperature. — calcium The chemical element calcium is the most abundant metallic element in the human body.

Calcium carbide (CaC₂) produces acetylene gas through a chemical reaction with water.12

When calcium carbide is exposed to water, it undergoes a decomposition reaction that yields acetylene gas and calcium hydroxide. The chemical equation for this process is:2

$C a C_{2} + 2 H_{2} O \to C_{2} H_{2} + C a (O H)_{2}$

Because this reaction releases a significant amount of heat, it must be performed under carefully controlled conditions. Industrially, this process serves as a primary source of acetylene for chemical manufacturing and oxyacetylene welding. On a smaller scale, the reaction has historically been used to generate acetylene for illumination due to the gas's ability to produce an extremely bright flame.21