Associate Safety Professional Practice Exam

What is true concerning the properties of calcium carbide?

1. It is non-reactive with water

2. It liberates carbon dioxide upon contact with water

3. It reacts violently with water liberating and igniting hydrogen

4. It is a common flammable liquid

The correct answer is: It reacts violently with water liberating and igniting hydrogen

Calcium carbide is known for its highly reactive nature, especially when it comes into contact with water. When calcium carbide comes into contact with water, it undergoes a chemical reaction that produces acetylene gas and calcium hydroxide. The reaction is exothermic and can generate enough heat to ignite the acetylene gas, which is flammable and can lead to explosive situations if in a confined space or at high concentrations. This property highlights the importance of handling calcium carbide with care, especially around moisture. The liberated hydrogen gas from this reaction poses significant hazards as it is highly flammable and can ignite in the presence of an ignition source. The other options do not accurately describe calcium carbide's behavior. For example, its non-reactivity with water is incorrect as it reacts vigorously, and it's not a flammable liquid; instead, it produces flammable gas upon reaction with water. Thus, the correct characterization is that calcium carbide reacts violently with water.