In the preparation of amorphous silicon, HF acid is used to remove

Options

A. Mg
B. `SiO_(2)`
C. `Si `
D. none of these

Explanation

**Step-by-Step Solution:**

1. **Understanding the Context**: In the preparation of amorphous silicon, various chemical reactions are involved. One of the key components that need to be addressed is the presence of silicon dioxide (SiO2).

2. **Role of HF Acid**: Hydrofluoric acid (HF) is specifically used to react with silicon dioxide. The reaction between HF and SiO2 is crucial for the removal of silicon dioxide from the mixture.

3. **Chemical Reaction**: The reaction can be represented as:
\[ \text{SiO}_2 + 4 \text{HF} \rightarrow \text{SiF}_4 + 2 \text{H}_2\text{O} \]
In this reaction, silicon dioxide reacts with hydrofluoric acid to produce silicon tetrafluoride (SiF4) and water (H2O).

4. **Removal of Byproducts**: The formation of SiF4 and water indicates that HF effectively removes SiO2 from the mixture, allowing for the preparation of amorphous silicon.

5. **Conclusion**: Therefore, in the preparation of amorphous silicon, HF acid is used to remove silicon dioxide (SiO2).