Question

Which silicon compound is used in machinery (with moving parts) like the use of an allotrope of carbon (crystalline) which possesses properties of both a covalent network solid and a molecular solid?
A. Silica gel
B. Zeolite
C. Silicone
D. Asbestos

Answer 1

Hint: Allotropy is the property of some chemical elements to exist in two or more different forms, in the same physical state, known as allotropes of the elements. Diamond is a covalent solid form of the element carbon with its atoms arranged in a crystal structure.

Complete step by step answer:
In the case of amorphous solid the physical properties like dielectric constant, melting point, refractive index, etc. do not change with change in direction. This is called isotropy. Amorphous solids do not have any definite arrangement or structure. They have a powder texture. For example, silica is an amorphous solid.
Silica gel can absorb water vapor that is why it is called a desiccant. Silica gel is nearly harmless that is why it is used as a desiccant in food products and medicine. This silica gel has any pours by which it can absorb moisture.

So, the correct answer is A.

Additional information:
During the production of glass, silica dust is heated and converted into molten glass. This molten glass gets cooled rapidly after removing it from the mold. Due to this rapid cooling cracking of glass happens. To prevent this another process is used by which gradually cooling of the glass or glass articles can be done. This process is called the annealing process.
In the process of annealing, a unique furnace which is called lehr is used. It is a long-sized oven that has different heating chambers of different temperatures. The glass articles move into all chambers to minimize the stress.

Note: Glass is produced from silica dust by heating followed by cooling after giving a proper shape. Due to the rapid cooling, cracking of glass happens. To prevent this another process is used by which gradually cooling of the glass or glass articles can be done. This process is called the annealing process.