Question

Why is plastic sulfur elastic in nature?

Answer 1

Hint: We can define allotrope as the property of few chemical elements to present in two (or) different forms, in the same physical state. Allotrope is related to different forms of the same element within the same phase that is solid, liquid (or) gas. For example, oxygen has two allotropes that is dioxygen and ozone and exist in the solid, liquid and vapour phase.

Complete step by step answer:
We know that sulfur is the second member of the oxygen family and its atomic number is 16. 0.17% of the earth’s crust is made of sulfur. It is a non-metal and it is formed as a by-product after the production of natural gas.
We have to know that sulfur has a number of structures in the same physical state. Rhombic sulfur and monoclinic sulfur are the two important crystalline structures. Rhombic sulfur is also called as $\alpha - $sulfur and monoclinic sulfur is called as $\beta - $sulfur.
The other allotropes of sulfur are colloidal sulfur, milk of sulfur, amorphous sulfur, insoluble sulfur, fibrous sulfur etc.
We have to know that amorphous sulfur is the other name for plastic sulfur. It is a quenched product of sulfur. It is otherwise known $\gamma - $sulfur. Plastic sulfur is a tough elastic material, which is formed when molten sulfur is poured into cold water.
We can prepare plastic sulfur by rapid cooling of the molten sulfur by pouring it into cold water. Yellow rubbery ribbons of sulfur are produced. They are soft and could easily be stretched. Plastic sulfur is a supercooled liquid.
Plastic sulfur is elastic because sulfur is yellow, powdery form is an octahedral ring. The ring is broken by heat. When we melt molten sulfur by immersing it into water, it produces a series of covalent chains (or) bonds, similar to polymer of carbon. This is the reason for the elastic nature of plastic sulfur.

Note:
 We can remember some properties of plastic sulfur as,
1.It appears dark brown rubber like mass.
2.The density of plastic sulfur is $1.92\,g/mL$.
3.Plastic sulfur is insoluble in carbon disulfide.
4.The melting point of sulfur is ${170^ \circ }C$.
5.Some of the uses of sulfur are,
6.Used in vulcanization of rubber.
7.Used as insecticides in crops.
8.Used in manufacturing bleaching agents
9.Used in the production of carbon disulfide that is used as skin ointments.