Question

The increasing order of field strength of ligands in the spectrochemical series is:

• A. \( {CO}<{H}_2{O}<{Cl}^-<{I}^- \)
• B. \( {Cl}^-<{H}_2{O}<{CO}<{I}^- \)
• C. \( {H}_2{O}<{CO}<{F}^-<{Cl}^- \)
• D. \( {H}_2{O}<{F}^-<{CO} \)
• E. \( {I}^-<{Cl}^-<{H}_2{O}<{CO} \)

Hint:

Stronger field ligands like CO cause larger splitting of \( d \)-orbitals compared to weaker field ligands like iodide (\( I^- \)).

Answer 1

Answer: (E)

The spectrochemical series arranges ligands based on their ability to split the \( d \)-orbitals in transition metal complexes. 
The increasing order of field strength (weak field to strong field ligands) is: \[ {I}^-<{Cl}^-<{H}_2{O}<{CO} \] Iodide (\( {I}^- \)) is a weak field ligand, while carbon monoxide (CO) is a strong field ligand.