Question

Diamond is harder than graphite because:

• A. graphite is planar
• B. diamond has free electron.
• C. graphite has $s{p}^3$ hybridization
• D. none of above

Answer 1

The correct option is D none of above

Diamond is harder than graphite as it is a crystalline form of carbon and each carbon is bonded with four other carbon atoms with a strong covalent bond where as the graphite is amorphous allotrope of carbon. So none of the above is correct answer
Hence option $D$ is correct.