Barium ions, CN− and Co2+ form an ionic complex. If this complex is 75% ionized in an aqueous solution with Vant Hoff factor(i) equal to four and the paramagnetic moment is found to be 1.73 BM (due to spin only) then the hybridization state of Co(II) in the complex will be:

Explanation

The complex is 75% ionized, leading to significant dissociation, which implies the presence of multiple ions. The Vant Hoff factor (i) of 4 supports this, indicating a highly charged complex. The paramagnetic moment of 1.73 BM suggests a single unpaired electron, which is characteristic of a low-spin octahedral complex involving Co(II). In such a configuration, the d2sp3 hybridization aligns with the octahedral geometry and the observed paramagnetic properties. Other hybridizations like sp3d, sp3d2, and dsp3 do not align with the given data as they suggest geometries or electron arrangements that are not consistent with the observed properties.