Chemistry - Coordination Chemistry Question with Solution | TestHub

According to the spectrochemical series, the arrangement of ligands in the increasing order of their crystal field splitting energy (CFSE) or field strength is:

${\text{I}}^{-}<{\text{Br}}^{-}<{\text{SCN}}^{-}<{\text{Cl}}^{-}<{\text{S}}^{2-}<{\text{F}}^{-}<{\text{OH}}^{-}<{\text{C}}_2{\text{O}}_4^{2-}<{\text{H}}_2\text{O}<{\text{NCS}}^{-}<{\text{edta}}^{4-}<{\text{NH}}_3<\text{en}<{\text{CN}}^{-}<\text{CO}$

From the given ligands, the decreasing order of field strength is:

$\text{CO}>{\text{NH}}_3>{\text{H}}_2\text{O}>{\text{Cl}}^{-}$

Answer: $\text{CO}>{\text{NH}}_3>{\text{H}}_2\text{O}>{\text{Cl}}^{-}$