Which of the following is an allotrope of carbon?

• A. Graphite
• B. Methane
• C. Diamond
• D. Carbon dioxide

Answer: (C)

Verified step by step guidance

1. Understand the concept of allotropes: Allotropes are different structural forms of the same element in the same physical state, where atoms are bonded together in different ways.
2. Identify the element in question: Here, the element is carbon.
3. Recall common allotropes of carbon: The well-known allotropes of carbon include graphite, diamond, and graphene, all of which consist solely of carbon atoms arranged differently.
4. Analyze each option: Graphite and diamond are both allotropes of carbon because they are different structural forms of carbon atoms. Methane (CH\_4) and carbon dioxide (CO\_2) are compounds containing carbon but are not allotropes since they include other elements.
5. Conclude that the correct answer is an allotrope of carbon: Diamond is indeed an allotrope of carbon, as it is a pure form of carbon with a distinct crystal structure.