Which will reduce zinc oxide to zinc?

Options

A. Mg
B. Pb
C. CU
D. Fe

Explanation

To determine which substance can reduce zinc oxide (ZnO) to zinc (Zn), we need to analyze the reduction potentials of the given substances: magnesium (Mg), lead (Pb), copper (Cu), and iron (Fe). The strongest reducing agent will be the one with the most negative reduction potential, as it can donate electrons more readily.

### Step-by-Step Solution:

1. **Identify the Reduction Reaction**:
The reduction of zinc oxide can be represented as:
\[ \text{ZnO} + 2e^- \rightarrow \text{Zn} + \text{O}^{2-} \]
This shows that zinc oxide is being reduced to zinc by gaining electrons.

2. **Check the Standard Reduction Potentials**:
The standard reduction potentials (E°) for the relevant half-reactions are:
- For Zn²⁺ + 2e⁻ → Zn: E° = -0.76 V
- For Mg²⁺ + 2e⁻ → Mg: E° = -2.37 V
- For Pb²⁺ + 2e⁻ → Pb: E° = -0.13 V
- For Cu²⁺ + 2e⁻ → Cu: E° = +0.34 V
- For Fe²⁺ + 2e⁻ → Fe: E° = -0.44 V

3. **Determine the Strongest Reducing Agent**:
The strongest reducing agent will be the one with the most negative E° value, as it can reduce other species more effectively. In this case:
- Mg has the most negative potential (-2.37 V), making it the strongest reducing agent among the options.

4. **Conclusion**:
Since magnesium has the lowest (most negative) reduction potential, it can effectively reduce zinc oxide to zinc. Therefore, the answer to the question is:
\[ \text{Mg (Magnesium)} \]

### Final Answer:
**Magnesium (Mg) will reduce zinc oxide to zinc.**

---