Correct increasing order for the wavelength of absorption in the visible region for the complexes of `Co^(3+)` is:

Options

A. `[Co(CN)_(6)]^(3-),[Co(NH_(3))_(6)]^(3+), [Co(NH_(3))_(5)(H_(2)O)]^(3+)[Co(NH_(3))_(5)Cl]^(+2)`
B. `[Co(CN)_(6)]^(3-),[Co(NH_(3))_(5)(H_(2)O)]^(3+)[Co(NH_(3))_(5)Cl]^(+2)[Co(NH_(3))_(6)]^(3+)`
C. `[Co(NH_(3))_(6)]^(3+),[Co(NH)_(6)]^(3-),[Co(NH_(3))_(5)(H_(2)O)]^(3+)[Co(NH_(3))_(5)Cl]^(+2)`
D. `[Co(NH_(3))_(5)Cl]^(+2),[Co(NH_(3))_(5)(H_(2)O)]^(3+),[Co(NH_(3))_(6)]^(3+),[Co(CN)_(6)]^(3-)`

Answer

A

Explanation

Strength of ligands attached with `Co^(3+)` ion is in the order of `CN^(-) gt NH_(3) gt H_(2)O gt Cl^(-)`. So order of spliting (value of `Delta_(0)`) will be in the same order.
`therefore" Wave length absorbing light "alpha=(1)/(Delta_(0))`