Question

Diamond and graphite are shown to be allotropic forms of carbon by the fact that

• A. diamond is hard but graphite is soft
• B. diamond is transparent while graphite is opaque
• C. they have different crystal structures
• D. both form $\ce{CO_2}$ when burnt.

Answer 1

Answer: (D)

both form $\ce{CO_2}$ when burnt.

Answer 2

Diamond and graphite are allotropes of carbon because both on burning produce ${CO_2}$ and thus show similar chemical properties.