Question

What is the name of this compound \[Si{{O}_{2}}\]?
A. Silicon oxide
B. Silica
C. Silicate
D. Silicones

Answer 1

Hint: This compound has been a very serious cause of respiratory diseases in cement factory workers, when inhaled as minute particles.

Complete step by step answer:
\[Si{{O}_{2}}\] is the chemical formula for silicon dioxide, which is also known as silica. It is present in nature as quartz, which comprises more than 10% by mass of the earth's crust.
Production of Silicon Dioxide –
Amorphous silica (or precipitated silica) is obtained by the acidification of sodium silicate solutions. Silica gel is washed, dehydrated to produce a colourless microporous silica. The reaction involving a trisilicate along with sulfuric acid is as given below –
\[N{{a}_{2}}S{{i}_{3}}{{O}_{7}}+{{H}_{2}}S{{O}_{4}}\to \text{ }3Si{{O}_{2}}+N{{a}_{2}}S{{O}_{4}}+{{H}_{2}}O\]
Silicon Dioxide Reactions
Silica gets converted to silicon by reducing it with carbon.
Fluorine when reacted with silicon dioxide, produces \[Si{{F}_{4}}\] and \[{{O}_{2}}\].
Silicon dioxide reacts with hydrofluoric acid to produce hexafluorosilicic acid \[\left( {{H}_{2}}Si{{F}_{6}} \right)\].
\[Si{{O}_{2}}+6HF\to {{H}_{2}}Si{{F}_{6}}+2{{H}_{2}}O\]
Uses of silica –
There are many uses of silica, for example - in the cement industry, in the production of glass, as a sedative, anti-caking agent in powdered foods, in hydraulic fracturing, etc.
Therefore, the answer is option (b) – \[Si{{O}_{2}}\] is the name of Silica.

Additional information: Inhaling silica is one of the leading causes for respiratory diseases in cement factory workers.

Note: In the majority of silicates, the silicon atom shows tetrahedral geometry, with four oxygen atoms surrounding a central Silicon atom. The most common example is seen in the quartz polymorphs, which is a 3-dimensional network solid in which each silicon atom is covalently bonded to 4 oxygen atoms in a tetrahedral manner.