In both the complexes, Fe is in \(+2\) oxidation state with \(d^6\) configuration. This means that it has four unpaired electrons. Both \(\mathrm{CN}^{-}\)ion and \(\mathrm{H}_2 \mathrm{O}\) molecules act as ligands occupy different relative positions in the spectrochemical series. They differ in crystal field splitting energy \(\left(\Delta_0\right)\). Quite obviously, they absorb radiations corresponding to different wavelengths and frequencies from the visible region of light, (VIBGYOR) and the transmitted colours are also different. This means that the complexes have different colours in solutions.