What happens when calcium carbide is treated with water?

Options

A. Ethane is formed
B. Methane and ethane are formed
C. Ethyne is formed
D. Ethene and ethyne are formed.

Explanation

To solve the question "What happens when calcium carbide is treated with water?", we can follow these steps:

### Step 1: Identify the Reactants
The reactants in this reaction are calcium carbide (CaC₂) and water (H₂O).

### Step 2: Write the Chemical Reaction
When calcium carbide reacts with water, it produces two products: calcium hydroxide (Ca(OH)₂) and acetylene (C₂H₂). The balanced chemical equation for the reaction is:
\[ \text{CaC}_2 + 2 \text{H}_2\text{O} \rightarrow \text{Ca(OH)}_2 + \text{C}_2\text{H}_2 \]

### Step 3: Identify the Products
The products of this reaction are:
1. Calcium hydroxide (Ca(OH)₂), which is a strong base and is also known as slaked lime.
2. Acetylene (C₂H₂), which is a flammable gas and is also known by its IUPAC name, ethyne.

### Step 4: Discuss the Properties of the Products
- **Calcium Hydroxide (Ca(OH)₂)**: This compound is a white solid that is slightly soluble in water, forming a basic solution.
- **Acetylene (C₂H₂)**: This is a colorless gas that is flammable and can be used as a fuel in welding and cutting metals. It is important to note that acetylene can contain impurities like phosphine and arsine when generated from calcium carbide.

### Step 5: Conclusion
When calcium carbide is treated with water, it produces calcium hydroxide and acetylene gas. The reaction is exothermic, meaning it releases heat, which can ignite the acetylene gas.