[Fe(CN)6]4- and [Fe(H2O ) 6]2+ show different colours in dilute solution because

Question

[Fe(CN)6]4- and [Fe(H2O ) 6]2+ show different colours in dilute solution because (A) CN- is a strong field ligand and H2O is a weak field ligand hence magnitude of CFSE is different (B) both CN- and H2O absorb same wavelength of energy (C) complexes of weak field ligands are generally colourless (D) the sizes of CN- and H2O are different hence their colours are also different

Tardigrade Admin · Accepted Answer

.Fe ( CN )6]4- ⇒ Fe 2+ ⇒ [ Ar ] 3 d 6 Where Fe 2+= CN arrow Strong field ligand. So, the energy gap is high. .Fe ( H 2 O )6]2+ ⇒ Fe 2+ ⇒ [ Ar ] 3 d 6 Where H 2 O = Weak field ligand. Energy gap is low.

Q. $[F e (CN)_{6}]^{4 -}$ and $[F e (H_{2} O)_{6}]^{2 +}$ show different colours in dilute solution because

$C N^{-}$ is a strong field ligand and $H_{2} O$ is a weak field ligand hence magnitude of $CFSE$ is different

both $C N^{-}$ and $H_{2} O$ absorb same wavelength of energy

complexes of weak field ligands are generally colourless

the sizes of $C N^{-}$ and $H_{2} O$ are different hence their colours are also different

$F e (CN)_{6}]^{4 -} \Rightarrow F e^{2 +} \Rightarrow [A r] 3 d^{6}$
Where $F e^{2 +} = CN \to$ Strong field ligand.
So, the energy gap is high.
$F e (H_{2} O)_{6}]^{2 +} \Rightarrow F e^{2 +} \Rightarrow [A r] 3 d^{6}$
Where $H_{2} O =$ Weak field ligand.
Energy gap is low.

Q. [Fe(CN)6​]4− and [Fe(H2​O)6​]2+ show different colours in dilute solution because

CN− is a strong field ligand and H2​O is a weak field ligand hence magnitude of CFSE is different

both CN− and H2​O absorb same wavelength of energy