Calcium carbide (CaC2) and water (H2O) react chemically when mixed. The reaction produces calcium hydroxide [Ca(OH)2] and acetylene gas (C2H2). This reaction is exothermic, meaning it releases heat. The heat produced can cause the mixture to ignite, resulting in a flammable and explosive reaction. Therefore, it is not recommended to mix calcium carbide and water directly, as it poses safety hazards. Proper safety measures and controlled conditions are necessary when handling and using calcium carbide.