The following sequence of reactions is used to convert borax into boron (B).
`Na_(2)underset("Borax")([B_(4)O_(5)(OH)_(4)]).8H_(2)O overset(x)toH_(3)BO_(3)overset(Delta)toB_(2)O_(3) overset(Y)to underset("Boron")(B)`
Reagents X and Y are respectively

Options

A. Acid, Al
B. Base, C
C. Base, Fe
D. Acid, Mg

Answer

To convert borax (Na₂B₄O₅(OH)₄·8H₂O) into boron (B), we need to identify the reagents X and Y in the sequence of reactions provided. Here’s the step-by-step breakdown of the reactions involved:

### Step 1: Conversion of Borax to Boric Acid
1. **Starting Material**: Borax (Na₂B₄O₅(OH)₄·8H₂O).
2. **Reagent X**: To convert borax into boric acid (H₃BO₃), we need an acid. Common acids used for this purpose include hydrochloric acid (HCl) or sulfuric acid (H₂SO₄).
3. **Reaction**:
\[ \text{Na}_2\text{B}_4\text{O}_5(\text{OH})_4 \cdot 8\text{H}_2\text{O} + \text{HCl (or H}_2\text{SO}_4) \rightarrow \text{H}_3\text{BO}_3 + \text{NaCl (or Na}_2\text{SO}_4) + \text{H}_2\text{O} \]
4. **Conclusion**: Thus, reagent X is an acid (HCl or H₂SO₄).

### Step 2: Heating Boric Acid to Form Boron Trioxide
1. **Next Step**: The boric acid obtained from the previous reaction is then heated.
2. **Reaction**:
\[ \text{H}_3\text{BO}_3 \xrightarrow{\Delta} \text{B}_2\text{O}_3 + \text{H}_2\text{O} \]
3. **Conclusion**: Heating boric acid results in the formation of boron trioxide (B₂O₃).

### Step 3: Conversion of Boron Trioxide to Boron
1. **Reagent Y**: To convert boron trioxide (B₂O₃) into boron (B), we need a reducing agent. Common reducing agents include magnesium (Mg) or sodium (Na).
2. **Reaction**:
\[ \text{B}_2\text{O}_3 + 3\text{Mg} \rightarrow 2\text{B} + 3\text{MgO} \]
or
\[ \text{B}_2\text{O}_3 + 6\text{Na} \rightarrow 2\text{B} + 3\text{Na}_2\text{O} \]
3. **Conclusion**: Thus, reagent Y can be either magnesium or sodium.

### Final Answer
- **Reagent X**: Acid (HCl or H₂SO₄)
- **Reagent Y**: Magnesium (Mg) or Sodium (Na)

### Summary of Options
- Based on the options provided, the correct reagents are:
- Reagent X: Acid
- Reagent Y: Magnesium (Mg)