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The p-Block Elements — Chemistry STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 ScienceChemistryThe p-Block Elements3 Marks
Question
Explain the following reactions:
Silicon dioxide is treated with hydrogen fluoride.
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Answer

When silicon dioxide ($SiO_2$​​​​​​​) is heated with hydrogen fluoride (HF), it forms silicon tetrafluoride ($SiF_4$​​​​​​​). Usually, the Si-O bond is a strong bond and it resists any attack by halogens and most acids, even at a high temperature. However, it is attacked by HF.
$\text{SiO}_4+4\text{HF}\rightarrow \text{SiF}_4+2\text{H}_2\text{O}$
The $SiF_4$​​​​​​​ formed in this reaction can further react with HF to form hydrofluorosilicic acid.
$\text{SiF}_4+2\text{HF} \rightarrow \text{H}_2\text{SiF}_6$

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