Question

Assertion (A) : Graphite is used as a lubricant.
Reason (R) : Graphite has a layer structure.

• A. Both A and R are true and R is correct explanation of A.
• B. Both A and R are true and R is not correct explanation of A.
• C. A is true but R is false.
• D. A is false but R is true.

Answer 1

Answer: (B)

Both A and R are true and R is not correct explanation of A.

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. Thus, one layer can slide over another and thus, it can be used as a lubricant.