Concept: Hybridization and Percentage of p-character

The percentage of p-character in a hybrid orbital depends on the type of hybridization. Hybridization is the mixing of atomic orbitals to form new hybrid orbitals with different energies, shapes, etc. The number of hybrid orbitals formed is equal to the number of atomic orbitals mixed.

Why (C) is correct:

• Graphite: In graphite, each carbon atom is sp² hybridized. An sp² hybrid orbital is formed by mixing one s-orbital and two p-orbitals. Therefore, out of 3 hybrid orbitals, 2 are p-orbitals. The percentage of p-character is $(2/3)\times 100\%=66.67\%$, which is approximately 67%.
• Diamond: In diamond, each carbon atom is sp³ hybridized. An sp³ hybrid orbital is formed by mixing one s-orbital and three p-orbitals. Therefore, out of 4 hybrid orbitals, 3 are p-orbitals. The percentage of p-character is $(3/4)\times 100\%=75\%$.

Thus, the percentage of p-character in graphite and diamond are approximately 67% and 75% respectively.

Option Analysis:

• A) 33 and 25: Incorrect. This would imply sp and sp³ hybridization with incorrect p-character for sp³.
• B) 50 and 75: Incorrect. 50% p-character corresponds to sp hybridization, not sp².
• C) 67 and 75: Correct, as explained above.
• D) 33 and 75: Incorrect. 33% p-character would imply sp² hybridization for s-character, not p-character.

Correct Answer: (C)