Calcium Carbide (CaC₂): Basic Information
1. Definition and Chemical Formula
Calcium carbide, with the chemical formula CaC₂, is an inorganic compound commonly known as carbide or electric stone. It is a reactive solid at room temperature and belongs to the class of ionic compounds.
2. Physical Properties
Appearance: Grayish-black crystalline solid with a rough texture.
Odor: Odorless in dry conditions, but reacts with moisture to release acetylene gas (C₂H₂), which has a garlic-like odor.
Hygroscopicity: Reacts vigorously with water, requiring storage in dry, airtight containers.
3. Chemical Properties
Reaction with Water:CaC2+2H2O→C2H2↑+Ca(OH)2Produces flammable acetylene gas and calcium hydroxide.
Reaction with Acids:CaC2+2HCl→C2H2↑+CaCl2Generates acetylene and calcium chloride.
4. Production
Synthesized via high-temperature reaction of coke (carbon) and lime (calcium oxide) in electric arc furnaces (~2000–2200°C):
CaO+3C→CaC2+CO↑
5. Key Uses
Acetylene Production: Primary use in generating acetylene for welding/cutting metals (oxy-acetylene torches).
Organic Synthesis: Acetylene is a precursor for plastics (e.g., PVC), rubber, and synthetic fibers.
Chemical Industry: Used to produce calcium cyanamide (fertilizer) and ethyne derivatives.
6. Safety Considerations
Water Reactivity: Store away from moisture to prevent acetylene release.
Fire/Explosion Risk: Acetylene is highly flammable; ensure proper ventilation.
Corrosive Byproducts: Calcium hydroxide (slaked lime) can cause skin/eye irritation. Use protective gear.
