Question

Quartz is a crystalline variety of:
A. Silicon carbide
B. Sodium silicate
C. Silica
D. Silicon

Answer 1

A crystalline compound is a type of compound in which the constituent particles, or atoms or molecules or ions of the compound are constituted in an orderly manner.
Silica is made up of one atom of silicon along with two atoms of oxygen.

Complete answer:
Quartz is a type of hard and crystalline mineral which is composed of silicon atoms as well as oxygen atoms. The linkage of these atoms are done in a continuous manner as $Si{{O}_{4}}$ molecules, where each of the oxygen of this molecule is shared between two more molecules of $Si{{O}_{4}}$, so the chemical formula of the overall simplest molecule becomes $Si{{O}_{2}}$. We know that, as a matter of fact, quartz is one of the most abundant minerals which is found on the earth surface.
Now if we consider the options which are given in the question, the first option says that silicon carbide is the constituent particle of quartz. We know that silicon carbide, which has the chemical formula $SiC$, is clear from the chemical formula and the name that it contains carbon along with silicon, and we know that quartz doesn’t have carbon content, so this option is incorrect.
If we consider option B, it says sodium silicate is the constituent particle of quartz, but we know that the sodium silicate will have sodium in it, and it has a chemical formula $N{{a}_{2}}Si{{O}_{3}}$. And again, this option is incorrect as we know that the quartz doesn’t have sodium content.
Now in the third option we see that silica is there, and as we have discussed silica is nothing but the silicon dioxide which is the overall formula for the constituent particles of quartz, hence the correct answer would be option C.
And lastly option D, says that quartz is made up of silicon, which is only partially true, as silicates are made up of silicon as well as oxygen, so the option D would be incorrect.

Therefore, the correct answer is option (C).

Note: Quartz is made up of atoms of silicon and oxygen combined with each other in an orderly manner. The simplest overall molecular formula of the constituent particles of quartz is $Si{{O}_{2}}$, silicon dioxide, or silicates.