Question

The amorphous form of silica is:

• A. Quartz
• B. Kieselguhr
• C. Cristobalite
• D. Tridymite

Answer 1

The correct option is B

Kieselguhr

Silicate: An anions consisting of silicon and oxygen.

Silicate anions are often large polymeric molecules with an extensive variety of structures, including chains and rings

They usually have the general formula ${\left[{\mathrm{SiO}}_{4-\mathrm{x}}^{(4-2\mathrm{x})-}\right]}_{\mathrm{n}}$
where 0 ≤ x < 2.

Explanation of correct option

(B) Kieselguhr-It is a mass of hydrated silica $\left({\mathrm{SiO}}_2\right)$ formed from skeletons of minute plants known as diatoms. It is a highly porous and absorbent material used in the manufacture of dynamite.

Explanation of Incorrect option

Three-dimensional sheet silicates: These silicates involve all four oxygen atoms in sharing with adjacent ${\mathrm{SiO}}_2$ tetrahedra.
Examples: Quartz, Tridymite, Cristobalite, Feldspars, Zeolites, and Ultramarines.

Hence, Option(B) is correct.