Predict which of the following will be coloured `Fe^(3+)` and `Co^(2+)`. Give reasons for each.

Explanation

Leaving aside .(Cu)^(+) . (Sc)^(3+). which will be white [because of .3 (~d)^(10), 3 (~d)^(2). electronic arrangement], all others will be coloured because they have partially filled d-orbitals and thus will involve d-d transitions.