Q. Graphite is a soft solid lubricant extremely difficult to melt. The reason for this anomalous behaviour is that, graphite
A) Is a non-crystalline substance
B) Is an allotropic from of diamond
C) Has molecules of variable molecular masses like polymers
D) Has carbon atoms arranged in large plates of rings of strongly bound carbon atoms with weak interplate bonds
Explanation
(d)
C-atoms form covalently bonded plates (layers). Layers are bonded weakly together, that’s why one layer can slide over other cause lubricacy. Cannot be melted easily as large number of atoms being bonded strongly in the layer form big entity.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.