Question

The element carbon occurs in 3 allotropic forms X, Y, and Z. X is formed of hexagonal arrays placed in layers one above the other, while Y has a rigid three- dimensional structure. Z has carbon atoms arranged in football shape. Identify X, Y, and Z.
A) X: Graphite
     Y: Coke
     Z: Diamond
B) X: Fullerene
     Y: Coke
     Z: Graphite
C) X: Coke
     Y: Graphite
     Z: Fullerene
D) X: Graphite
     Y: Diamond
     Z: Fullerene

Answer 1

Hint: Allotropes are different forms of the same element bonded together differently without changing the chemical representation. It should be noted that carbon exists in three allotropic forms i.e. crystalline, amorphous and fullerene.

Complete step by step answer:
Carbon shows allotropism due to its catenation property and its ability to form \[p\pi - p\pi \] a bond.
Let us find what X represents:
In graphite, each carbon is \[s{p^2}\] hybridized and has a layered structure. Each layer consists of a hexagonal carbon ring. These layers are connected by van der Waals force. Here, each carbon has one free electron in p- orbital. So, it is a good conductor of electricity.
Let us find what Y represents:
In diamond, each carbon is joined to the other four carbons tetrahedrally and each carbon has \[s{p^3}\] hybridization. We know that diamonds do not have any free electrons. Hence, it is a bad conductor of electricity.
Let us find what Z represents:
The chemical representation of Fullerene is \[{C_{60}}\] and buckyballs are the most common type of fullerene which has football-like structure. We know that every ring in the structure of fullerene is aromatic and fullerene is used to make ball bearing.

Therefore, we can conclude that the correct answer to this question is option D.

Note:
Graphite is amorphous so it contains the layers placed one above the other and diamond is crystalline so it forms the three-dimensional structure. Fullerene contains the hexagonal six-membered ring and 12 pentagonal five-membered rings.