The wavelengths of light absorbed for the following complexes are in the order (I) [Co(NH3)6]3+ ; (II) [Co(H2O)6]3+ ; (III) [Co(CN)6]3- ; (IV) [Co(NH3)5(H2O)]3+ ; (V) [CoF6]3-
- III < IV < I < II < V
- III < I < IV < V < II
- III < I < IV < II < V
- III < I < II < IV < V
Answer
(3) III < I < IV < II < V
Solution
All are Co(III), d6 complexes; the absorbed wavelength 1 o.
Spectrochemical series: F- < H2O < NH3 < CN-
o: III (CN-) > I (6NH3) > IV (5NH3 + H2O) > II (6H2O) > V (F-)
wavelength absorbed: III < I < IV < II < V
Answer: (3)