In which of the following complex ion, the central metal ion is in a state of s p³ d² hybridisation?

Step-by-step solution

In [ CoF ₆ ]³⁻, F ⁻ is a weak ligand. It cannot pair up d -electrons and form outer orbital octahedral complex while NH ₃ and CN ⁻ are strong ligand. In [ CoF ₆ ]³⁻ , outer orbital 4 d is used in hybridisation. Thus, it is called outer orbital or high spin or spin free complex. Co =[ Ar ] 3 d⁷ 4 s² and Co ³⁺=[ Ar ] 3 d⁶