`Be_(2)C and Al_(4)C_(3)` are called

Options

A. ethanides
B. methanides
C. carbonides
D. acetylides

Explanation

To solve the question regarding the compounds \( \text{Be}_2\text{C} \) and \( \text{Al}_4\text{C}_3 \), we need to identify what these compounds are commonly called based on their reactions with water.

### Step-by-Step Solution:

1. **Identify the Compounds:**
- \( \text{Be}_2\text{C} \) is known as beryllium carbide.
- \( \text{Al}_4\text{C}_3 \) is known as aluminum carbide.

2. **Reaction with Water:**
- When beryllium carbide reacts with water, it undergoes hydrolysis:
\[ \text{Be}_2\text{C} + 4\text{H}_2\text{O} \rightarrow 2\text{Be(OH)}_2 + \text{CH}_4 \]
This reaction produces beryllium hydroxide and methane gas (\( \text{CH}_4 \)).

- Similarly, when aluminum carbide reacts with water, it also undergoes hydrolysis:
\[ \text{Al}_4\text{C}_3 + 12\text{H}_2\text{O} \rightarrow 4\text{Al(OH)}_3 + 3\text{CH}_4 \]
This reaction produces aluminum hydroxide and methane gas (\( \text{CH}_4 \)).

3. **Naming the Compounds:**
- Compounds that release methane gas upon hydrolysis are referred to as "methanides."
- Since both \( \text{Be}_2\text{C} \) and \( \text{Al}_4\text{C}_3 \) release methane when they react with water, they are classified as methanides.

4. **Conclusion:**
- Therefore, the correct answer to the question is that \( \text{Be}_2\text{C} \) and \( \text{Al}_4\text{C}_3 \) are called **methanides**.

### Final Answer:
**Methanides**