Question

Graphite is a soft solid lubricant extremely difficult to melt. The reason for this anomalous behavior of graphite :

• A. is carbon atoms are arranged in large plates of rings of strongly bound carbon atoms with weak interplate bonds
• B. is a non-crystalline substance
• C. has molecules of variable molecular masses like polymers
• D. is an allotropic form of diamond

Answer 1

The correct option is A is carbon atoms are arranged in large plates of rings of strongly bound carbon atoms with weak interplate bonds

Graphite has layer structure. Each layer is a planar sheet, composed of hexagonal rings of carbon atoms, with 3 electrons of each atom involved in strong single bonds with three adjacent atoms of hexagonal ring. The extra electron makes a very weak bond with the adjacent layer. The inter-layer distance can be easily changed. This makes graphite very soft. The strong bonds within the layer make it difficult to melt, as these bonds can be broken at only very high temperatures.