The final product formed when silica reacts with hydrogen fluoride is

Options

A. SiF
B. `H_(2) Si F_(6)`
C. `H_(2) Si F_(4)`
D. `H_(2) Si O_(3)`

Answer

To determine the final product formed when silica (SiO2) reacts with hydrogen fluoride (HF), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reactants**: The reactants in this reaction are silica (SiO2) and hydrogen fluoride (HF).

2. **Write the Initial Reaction**: When silica reacts with hydrogen fluoride, the reaction can be represented as:
\[ \text{SiO}_2 + 4 \text{HF} \rightarrow \text{SiF}_4 + 2 \text{H}_2\text{O} \]
Here, silica reacts with four moles of HF to produce silicon tetrafluoride (SiF4) and water (H2O).

3. **Further Reaction of SiF4**: The silicon tetrafluoride (SiF4) can further react with another molecule of HF:
\[ \text{SiF}_4 + \text{HF} \rightarrow \text{H}_2\text{SiF}_6 \]
This reaction produces hexafluorosilicic acid (H2SiF6), which is a soluble compound.

4. **Final Product**: Therefore, the final product formed when silica reacts with hydrogen fluoride is hexafluorosilicic acid (H2SiF6).

5. **Conclusion**: Based on the reactions, the correct answer is H2SiF6.

### Final Answer:
The final product formed when silica reacts with hydrogen fluoride is **H2SiF6**.

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