Question

$\text{Si}{\text{O}}_2$ is soluble in:

• A. $H_{2}S{O}_4$
• B. $HN{O}_3$
• C. $HF$
• D. $HCl$

Answer 1

Answer: (C)

$\text{Si}{\text{O}}_{\text{2}}\text{.}$ is soluble in HF only. Therefore/HP cannot be stored in glass or silica bottles as it attack silicates as well as silica. $N{a}_{2}Si{O}_3+6HF\to N{a}_{2}Si{F}_6+3H_{2}O$ $CaSi{O}_3+6HF\to CaSi{F}_6+3H_{2}O$ $Si{O}_2+4HF\to Si{F}_4+2H_{2}O$ This action of HF on silica and silicates is used for etching glass.