Which of the following allotrope of carbon is a constituent of a lead pencil?
Graphite
Diamond
Lampblack
Soot
Correct answer is A
When an element exists in more than one crystalline form, those forms are called allotropes; the two most common allotropes of carbon are diamond and graphite.
Graphite is used in pencils and lubricants. It is a good conductor of heat and electricity. Its high conductivity makes it useful in electronic products such as electrodes, batteries, and solar panels.