Silica reacts with `HF` to produce

Options

A. `Si` and `HFO_(2)`
B. `SiF_(2)` and `H_(2)O`
C. `H_(2)[SiF_(6)]` and `H_(2)O`
D. `SiF_(4)` and `H_(2)O`

Answer

3

Explanation

Industrially `MF` is made by heating `CaF_(2)` with concentrated `H_(2)SO_(4)` However, it is important that `SiO_(2)` impurities are removed from the `CaF_(2)`, as otherwise they consume much of the `HF` produced:
`SiO_(2)(s)+4HF(aq.)rarrSiF_(4)(g)+2H_(2)O(l)`
`SiF_(4)(g)+2HF(aq.)rarrunderset("fluorosilic acid")((H^(+))_(2)SiF_(6)^(2-)(aq.))`