Final answer:
The central carbon in allene is sp hybridized and the terminal carbon atoms are sp² hybridized. Because of the perpendicular p orbitals forming pi bonds, the hydrogen atoms on the terminal carbon atoms are in perpendicular planes, making (c) the correct choice. Option C
Step-by-step explanation:
For the molecule allene, H2C=C=CH2, the central carbon atom is hybridized as sp, because it is involved in forming two pi (π) bonds, one with each of the adjacent carbon atoms. The carbon atoms at either end are hybridized as sp2.
Accordingly, the hybrid orbitals used by the carbon atoms in the molecule to form sigma (σ) bonds are sp hybrid orbitals for the central carbon and sp2 for the terminal carbons. Because the central carbon atom has two pi bonds formed from p orbitals that lie perpendicular to each other, the hydrogen atoms on the terminal carbons will be in perpendicular planes.
The bonding in allene is such that the central carbon forms a sigma bond with each of the adjacent carbons using its sp hybrid orbitals, while the unhybridized p orbitals on the central carbon atom overlap with the p orbitals from the terminal carbons to form the π bonds.
The terminal carbons use their sp2 hybrid orbitals to form sigma bonds with the hydrogen atoms, which results in the hydrogen atoms being in planes that are perpendicular to each other due to the linear arrangement of the double bonds. This results in the correct answer being (c) Hybridization: sp, Hydrogen atoms in perpendicular planes. Option C