Which of the following electropositive metal is used for the isolation of boron from `B_2O_3`?

Options

A. `Al`
B. `Zn`
C. `Mg`
D. `Au`

Answer

To isolate boron from \( B_2O_3 \), we need to identify the most electropositive metal that can react with \( B_2O_3 \). Let's break down the solution step by step.

### Step-by-Step Solution:

1. **Identify the Compound**: We start with the compound \( B_2O_3 \), which is boron trioxide. Our goal is to isolate boron from this compound.

**Hint**: Understand the chemical composition of the compound you are working with.

2. **Electropositive Metals**: We need to consider electropositive metals that can reduce \( B_2O_3 \). Electropositive metals are those that readily lose electrons to form positive ions. Common examples include aluminum (Al), magnesium (Mg), sodium (Na), and calcium (Ca).

**Hint**: Recall the properties of electropositive metals and their tendency to react with non-metals.

3. **Reactions with \( B_2O_3 \)**:
- When aluminum reacts with \( B_2O_3 \), it produces aluminum oxide (\( Al_2O_3 \)) and boron. However, aluminum is not the most electropositive metal available.
- On the other hand, magnesium is more electropositive than aluminum.

**Hint**: Compare the electropositivity of the metals in the options provided.

4. **Reaction with Magnesium**: When magnesium reacts with \( B_2O_3 \), the reaction can be represented as:
\[ 3Mg + B_2O_3 \rightarrow 3MgO + 2B \]
This reaction produces magnesium oxide (\( MgO \)) and boron. The boron produced in this reaction is more pure and in an amorphous form compared to the boron produced from aluminum.

**Hint**: Write down the balanced chemical equations to visualize the reactions.

5. **Conclusion**: Based on the above analysis, the most electropositive metal that can be used to isolate boron from \( B_2O_3 \) is magnesium.

**Final Answer**: The correct answer is Magnesium.