whih of the following ions gives(s) coloured aqeous solution?

Options

A. `Ni^(2+)`
B. `Fe^(2+)`
C. `Cu^(2+)`
D. `Cu^(+)`

Answer

ABC

Explanation

`Ni^(2+),Fe^(2+)` and `Cu^(2+)` and `2,4` and `1` unpaired electrons repectively. So in presence of ligands d-d transition take place and these hydrated ion produce colour in aqueous solution . `Cu^(+)` is diamagnetic with `3d^(10)` configuration, so no d-d transition is possible and thus colourless.