The aqueous solution of the following salts will be coloured in the case of

Options

A. `Zn(NO_3)_2`
B. `LiNO_3`
C. `Co(NO_3)_2`
D. `CrCl_3`

Answer

C, D

Explanation

`Co^(2+)`:
`Co(Z=27)=3d^74s^2`
`Co^(2+)=3d^7`
Two unpaired electrons are present
`Cr(Z=24)=3d^54s^1`
`Cr^(3+)=3d^3`
`CoNO_3)_2` and `CrCl_3` has unpaired electron, hence they are coloured.