Does silicon dioxide react with alkalis?

In my science class, I have been taught that silica (silicon dioxide/sand) has three properties, namely


1. It does not react with water.
2. It does not decompose with heat.
3. It does not react with acid.


However I think that if it does not react with acid, will it react with bases? I am just curious because if it does react, why does my textbook not say anything about that? 




It really does react:
\begin{align}
\ce{4HF + SiO2 &-> SiF4 + 2 H2O}\\
\ce{SiF4 + 2 HF &-> H2[SiF6]}\\
\ce{SiO2 + 2 NaOH &-> Na2SiO3 + H2O}\\
\ce{SiO2 + 2 F2 &-> SiF4 + O2}\\
\ce{SiO2 + 2 C &-> Si + 2 CO}\\
\ce{(2,1)Na2O + (1,1)SiO2 &-> Na4SiO4/Na2SiO3}\\
\ce{SiO2 + Si &-> 2 SiO}
\end{align}


 7

$\ce{SiO2}$ definitely reacts with strong bases like $\ce{NaOH}$ or $\ce{KOH}$ which is why such solutions should not be stored in glass bottles.


Concentrated and hot aqueous solution of $\ce{NaOH}$ can damage glassware in the course of several days. $\ce{KOH}$ or $\ce{NaOH}$ in methanol is even more potent. Reaction is obviously faster with finely divided $\ce{SiO2}$ 


$\ce{4NaOH + SiO2 -> Na4SiO4 + 2H2O}$


 2

Now, I realize that silicon dioxide is a very stable compound. However, there is an exception which is it will react react with a thing- Hydrofluoric acid ($\ce{HF}$)


The reaction is undergo like the equation below:


$$\ce{4HF(g) + SiO2(s) -> SiF4(g) + 2H2O(l)}$$


Only $\ce{HF}$ can react with sand ($\ce{SiO2}$), others chemical can't as sand is really that stable.


 1