The correct order of the wavelength of light absorbed by the following complexes is, A. [Co(NH3)6]3+ B. [Co(CN)6]3- C. [Cu(H2O)4]2+ D. [Ti(H2O)6]3+ Choose the correct answer from the options given below:
- C < D < A < B
- C < A < D < B
- B < D < A < C
- B < A < D < C
Answer
(4) B < A < D < C
Solution
∵ absorbed = hc ⇒ greater the crystal field splitting, shorter the wavelength absorbed.
As per NCERT (wavelength of light absorbed by complexes):
B. [Co(CN)6]3-: 310 nm (ultraviolet); CN- is a very strong field ligand.
A. [Co(NH3)6]3+: 475 nm (blue).
D. [Ti(H2O)6]3+: 498 nm (blue-green).
C. [Cu(H2O)4]2+: 600 nm (red); weak field H2O with a +2 ion.
∴ Wavelength absorbed: B < A < D < C
Answer: (4)