The magnesium oxide can be reduced to Mg by which of the following reducing agents?

Options

A. `CaC_(2)`
B. Coke powder
C. Cr powder
D. Si powder

Answer

To determine which reducing agents can reduce magnesium oxide (MgO) to magnesium (Mg), we need to analyze the given options and understand the reduction process.

### Step-by-Step Solution:

1. **Identify the Reduction Reaction**:
The reduction of magnesium oxide can be represented by the following chemical equation:
\[ \text{MgO} + \text{Reducing Agent} \rightarrow \text{Mg} + \text{Oxide of Reducing Agent} \]
Here, we need to find suitable reducing agents that can effectively donate electrons to reduce MgO to Mg.

2. **Evaluate the Given Reducing Agents**:
The reducing agents provided are:
- Calcium carbide (CaC₂)
- Chromium powder (Cr)
- Silicon powder (Si)
- Coke powder (C)

We will analyze each of these agents to see if they can reduce MgO.

3. **Calcium Carbide (CaC₂)**:
Calcium carbide can react with water to produce calcium hydroxide and acetylene gas. However, it can also act as a reducing agent in high-temperature reactions. The reaction can be represented as:
\[ \text{MgO} + \text{CaC}_2 \rightarrow \text{Mg} + \text{CaO} + \text{C}_2\text{H}_2 \]
Thus, calcium carbide can reduce MgO to Mg.

4. **Chromium Powder (Cr)**:
Chromium is a strong reducing agent and can reduce various metal oxides. The reaction can be represented as:
\[ \text{MgO} + \text{Cr} \rightarrow \text{Mg} + \text{CrO} \]
Therefore, chromium powder can also reduce MgO to Mg.

5. **Silicon Powder (Si)**:
Silicon can also act as a reducing agent for metal oxides. The reaction can be represented as:
\[ \text{MgO} + \text{Si} \rightarrow \text{Mg} + \text{SiO} \]
Hence, silicon powder can reduce MgO to Mg.

6. **Coke Powder (C)**:
Coke is generally used as a reducing agent in metallurgical processes, but it is not effective for reducing magnesium oxide directly under normal conditions. Therefore, coke powder is not suitable for this reaction.

7. **Conclusion**:
The reducing agents that can reduce magnesium oxide (MgO) to magnesium (Mg) are:
- Calcium carbide (CaC₂)
- Chromium powder (Cr)
- Silicon powder (Si)

### Final Answer:
The reducing agents that can reduce magnesium oxide (MgO) to magnesium (Mg) are calcium carbide, chromium powder, and silicon powder.