Question

Crystalline solids are:
(a) Glass
(b) Rubber
(c) Plastic
(d) Sugar

Answer 1

Hint: Diamond is an example of a crystalline solid in which the carbon atoms are arranged in a well-defined order. In Diamond, each tetravalent carbon atom is fused with four carbon atoms, and each of these four carbon atoms are further linked with four other carbons.

Complete Step by Step Solution:
Crystalline solid: The crystalline solid or crystal belongs to the class of solid material.
Inside the crystalline solid the constituent particle such as atoms, molecules, and ions are arranged in very well define uniform order in all directions.
- The crystalline solids possess sharp melting points along with well-defined faces and edges.
- The crystalline solids have an excellent tendency to diffract x-rays.
- The crystalline solids are also considered anisotropic in nature because their physical properties are different in all directions.
- Diamond, quartz, calcium fluoride (\[Ca{F_2}\]), silicon dioxide (\[Si{O_2}\]), and sugar are some of the best examples of such materials.
- The sugar exists in a cube-like crystalline form in which the sucrose molecules are arranged in well defined-manner in all directions.
- The crystalline solids have a wide range of applications. Diamond can be used in making beautiful jewellery whereas quartz is used in making watches and clocks.

Amorphous solid
- In their structure, the constituent atoms do not follow the regular three-dimensional arrangement.
- They do not have sharp or fixed melting points i.e., they have a wide range of melting temperatures.
- Amorphous solids are also considered isotropic in nature because their physical properties are the same in all directions.
- Glass, rubber, and plastic are non-crystalline or amorphous solids.
- Amorphous solids have various applications. For example, glass can be used in making various glassware. While the rubber can be used in making tubes, belts, and tires. Similarly, plastic also has applications in making various households.

Therefore, from the above discussion, option (D) will be the correct answer.

Note: Glass is also known as a supercooled liquid. The heat of fusion for amorphous solids cannot be defined correctly in comparison to crystalline solids.