Question

The most stable ion is ______.

Options

• [Fe(OH)₅]^3–

• [FeCl₆]^3–

• [Fe(CN)₆]^3–

• [Fe(H₂O)₆]³⁺

Answer 1

The most stable ion is `bbunderline([Fe(CN)_6]^(3–))` . 

Explanation:

CN⁻ is a strong-field ligand according to the spectrochemical series, and it forms a low-spin octahedral complex with maximum crystal field stabilization energy (CFSE), making it more stable than complexes with weak-field ligands such as H₂O, Cl⁻, or OH⁻.