Final answer:
The reaction between hydrogen fluoride and sand (silicon dioxide) is a synthesis reaction that forms silicon tetrafluoride and water. The reaction is significant because of the strong bond between silicon and fluorine. All common acids except hydrofluoric acid can be stored in glass due to this bond strength.
Step-by-step explanation:
The reaction that hydrogen fluoride undergoes when reacting with sand (silicon dioxide) is classified as a synthesis reaction. Specifically, it is the synthesis of silicon tetrafluoride (SiF4) from silicon dioxide and hydrofluoric acid. When silicon dioxide reacts with hydrofluoric acid, it produces silicon tetrafluoride and water as products.
The balanced chemical equation for this reaction is:
SiO₂ (s) + 4HF(g) → SiF4 (g) + 2H₂O(l)
This encompasses the preparation of silicon tetrafluoride, which proves to be a significant reaction due to the bond strength between silicon and fluorine, which is stronger than that of a silicon-oxygen bond. This is why it is possible to store all common acids, except hydrofluoric acid, in glass containers.