Question

The carbon pencil (commonly called lead pencil) is actually made of a mixture of graphite and

clay. In a particular batch of pencils, the percentage of graphite was increased.

A number of complaints were received from the users saying that the pencil was sliding on

paper and therefore it had become difficult to write. What is the probable reason for this?

a. graphite has a high melting point.

b. graphite is a form of carbon.

c. graphite is a lubricant.

d. graphite is a non-metal.​

Answer 1

Concept: Property of graphite.
Answer: The answer is option C.
Explanation:
•Graphite is made up of carbon atoms.
•The layers are weakly bonded together so they easily slide over each other and it also shows lower shearing strength under friction force.
•This makes graphite soft and slippery and gives it self-lubricating properties.
Hence, the correct answer is option C.