Beryllium and aluminium carbides contain

Options

A. ` C^(4-)`
B. `C_2^(2-)`
C. `C_3^(2-)`
D. `C^(4+)`

Answer

To solve the question regarding what Beryllium and Aluminum carbides contain, we need to analyze the structures and oxidation states of the carbides formed by these elements.

### Step-by-Step Solution:

1. **Identify the Carbides**:
- Beryllium carbide is represented as \( \text{Be}_2\text{C} \).
- Aluminum carbide is represented as \( \text{Al}_4\text{C}_3 \).

2. **Determine the Oxidation States**:
- For Beryllium carbide \( \text{Be}_2\text{C} \):
- Each Beryllium (Be) has an oxidation state of +2.
- The total positive charge from Beryllium is \( 2 \times (+2) = +4 \).
- To balance this, the carbon must have an oxidation state of -4.
- Therefore, in \( \text{Be}_2\text{C} \), the carbon is in the form of \( \text{C}^{4-} \).

3. **Analyze Aluminum Carbide**:
- For Aluminum carbide \( \text{Al}_4\text{C}_3 \):
- Each Aluminum (Al) has an oxidation state of +3.
- The total positive charge from Aluminum is \( 4 \times (+3) = +12 \).
- To balance this, the carbon must have an oxidation state of -12, which can be distributed among the three carbon atoms.
- Therefore, in \( \text{Al}_4\text{C}_3 \), we can express it as \( 3 \times \text{C}^{4-} \).

4. **Conclusion**:
- Both Beryllium and Aluminum carbides contain the anion \( \text{C}^{4-} \).
- The cations are \( \text{Be}^{2+} \) for Beryllium and \( \text{Al}^{3+} \) for Aluminum.

### Final Answer:
Beryllium and Aluminum carbides contain the anion \( \text{C}^{4-} \).

---