Which one of the following ionic species will impart colour to an aqueous solution ?

Options

A. `Ti^(4+)`
B. `Cu^(+)`
C. `Zn^(2+)`
D. `Cr^(3+)`

Answer

D

Explanation

In `Ti^(4+),Cu^(+) and Zn^(2+)`, all have electrons paired so all are diamagnetic . `Cr^(3+)` with electron configuration `[Ar]^(18)3d^(3)` has three unpaired electrons. So it underoes d-d transition of electrons in presence of ligands according to CFT and thus it is coloured.