Which of the following hybridization schemes allows the formation of at least one pi (π) bond?

• A. sp3d
• B. sp3d2
• C. sp3
• D. sp

Answer: (D)

Verified step by step guidance

1. Recall that pi (π) bonds are formed by the side-to-side overlap of unhybridized p orbitals. Therefore, for a pi bond to form, the atom must have at least one unhybridized p orbital available.
2. Analyze the hybridization schemes: sp3, sp3d, and sp3d2. Each hybridization involves mixing s, p, and sometimes d orbitals to form hybrid orbitals used in sigma (σ) bonding.
3. In sp3 hybridization, one s and three p orbitals mix, using all three p orbitals for hybridization, leaving no unhybridized p orbitals available for pi bonding.
4. In sp3d and sp3d2 hybridizations, the involvement of d orbitals along with s and p orbitals means that all p orbitals are also hybridized, leaving no unhybridized p orbitals for pi bonds.
5. In contrast, sp hybridization mixes one s and one p orbital, leaving two p orbitals unhybridized. These unhybridized p orbitals can overlap side-to-side to form pi bonds, allowing the formation of at least one pi bond.