In the industrial production of soluble sodium silicate (water glass), quartz sand (silicon dioxide, SiO2\text{SiO}_2SiO2) is reacted with concentrated sodium hydroxide (NaOH\text{NaOH}NaOH) at high temperatures.
The equation for the reaction is:
SiO2+2NaOH→Na2SiO3+H2O \text{SiO}_2 + 2\text{NaOH} \to \text{Na}_2\text{SiO}_3 + \text{H}_2\text{O} SiO2+2NaOH→Na2SiO3+H2OExplain, in terms of their acid-base properties, why silicon dioxide reacts with sodium hydroxide.
Part of the giant covalent structure of silicon dioxide is shown in the diagram below.
What does particle A represent? Give a reason for your answer.
Explain, in terms of its bonding and structure, why silicon dioxide has a very high melting point.
