Question

The most stable ion is :

• A. $\left[ Fe ( OH )_{5}\right]^{3-}$
• B. $\left[ FeCl _{6}\right]^{3-}$
• C. $\left[ Fe ( CN )_{6}\right]^{3-}$
• D. $\left[ Fe \left( H _{2} O \right)_{6}\right]^{3+}$

Answer 1

Answer: (C)

Stability of complex increases with increase in charge on the central metal ion increase with basic strength of ligand. $In\left[ Fe ( CN )_{6}\right]^{3-}$
oxidation state of Fe is +3 and basicity of $CN ^{-}$ is higher than $OH ^{-}, Cl ^{-}$ and $H _{2} O$.