Final answer:
The hybridization of the cobalt ion in [Co(NH₃)₆]³⁺ complex is d²sp³, and its magnetic behavior is diamagnetic. The correct option is C.
Step-by-step explanation:
The hybridization of the cobalt ion in [Co(NH₃)₆]³⁺ complex is d²sp³. In this complex, cobalt is in the +3 oxidation state, which means it has 7 d-electrons. The coordination number of cobalt in the complex is 6, and all the ligands are ammonia molecules. Since 6 ammonia ligands are present, cobalt will undergo dsp³ hybridization, which involves mixing of 1 d-orbital, 1 s-orbital, and 3 p-orbitals to form 5 hybrid orbitals. These hybrid orbitals will then form bonds with the ammonia ligands.
The magnetic behavior of the cobalt ion in [Co(NH₃)₆]³⁺ complex is diamagnetic. A diamagnetic substance is not attracted to a magnetic field and has all its electrons paired up. In the [Co(NH₃)₆]³⁺ complex, there are no unpaired electrons present, as all the bonding and non-bonding orbitals are completely filled.
Therefore, the correct option is C. d²sp³ and diamagnetic.