Which of the following complex ion is not expected to absorb visible light?

Options

A. (a) `[Ni(CN)_4]^(2-)`
B. (b) `[Cr(NH_3)_6]^(3+)`
C. (c) `[Fe(H_2O)_6]^(2+)`
D. (d) `[Ni(H_2O)_6]^(2+)`

Answer

A

Explanation

A transition metal complex absorbs visible light only when it has unpaired electron. `Ni^(2+)` in strong field ligand has configuration as