Silicon Dioxide MCQ - Practice Questions & Answers

JEE Main Chemistry High Weightage Chapters and Topics 2025

Quick Facts

SiO2 is considered one of the most asked concept.
8 Questions around this concept.

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Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : In expensive scientific instruments, silica gel is kept in watch-glasses or in semipermeable membrane bags.
Reason (R) : Silica gel adsorbs moisture from air via adsorption, thus protects the instrument from water corrosion (rusting) and / or prevents malfunctioning.
In the light of the above statements, choose the correct answer from the options given below :

Both (A) and (R) are true but (R) is not the correct explanation of (A)

(A) is false but (R) is true

Both (A) and (R) are true and (R) is the correct explanation of (A)

(A) is true but (R) is false

View Solution

The structure of silicon dioxide is characterized by:

Covalent bonds between silicon and oxygen atoms

Ionic bonds between silicon and oxygen atoms

Metallic bonds between silicon and oxygen atoms

Hydrogen bonds between silicon and oxygen atoms

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Concepts Covered - 0

SiO2

95% of the earth’s crust is made up of silica and silicates. Silicon dioxide, commonly known as silica, occurs in several crystallographic forms. Quartz, cristobalite and tridymite are some of the crystalline forms of silica, and they are interconvertible at suitable temperature. Silicon dioxide is a covalent, three-dimensional network solid in which each silicon atom is covalently bonded in a tetrahedral manner to four oxygen atoms. Each oxygen atom in turn covalently bonded to another silicon atoms as shown in figure. Each corner is shared with another tetrahedron. The entire crystal may be considered as giant molecule in which eight-membered rings are formed with alternate silicon and oxygen atoms.

Silica in its normal form is almost non reactive because of very high Si—O bond enthalpy. It resists the attack by halogens, dihydrogen and most of the acids and metals even at elevated temperatures. However, it is attacked by HF and NaOH.

$\begin{array}{l}{\mathrm{SiO}_{2}+2 \mathrm{NaOH} \rightarrow \mathrm{Na}_{2} \mathrm{SiO}_{3}+\mathrm{H}_{2} \mathrm{O}} \\ {\mathrm{SiO}_{2}+4 \mathrm{HF} \rightarrow \mathrm{SiF}_{4}+2 \mathrm{H}_{2} \mathrm{O}}\end{array}$

Quartz is extensively used as a piezoelectric material; it has made possible to develop extremely accurate clocks, modern radio and television broadcasting and mobile radio communications. Silica gel is used as a drying agent and as a support for chromatographic materials and catalysts. Kieselghur, an amorphous form of silica is used in filtration plants.