Question

Which of the following complex ions is expected to absorb visible light?
A. `[Sc(H_(2)O)_(3)(NH_(3))_(3)]^(3+)`
B. `[Ti(en)_(2)(NH_(3))_(2)]^(4+)`
C. `[Cr(NH_(3))_(6)]^(3+)`
D. `[Co(en)_(3)]^(3+)`

Answer 1

Correct Answer - C
In `[Cr(NH_(3))_(6)[^(3+),Cr" is present as "Cr^(3+), Cr^(3+)=[Ar]3d^(3), 4s^(0)`

Since, this complex has three unpaired electrons, excitation of electrons is possible and thus, it is expected that this complex will absorb visible light.