`[Se(H_2 O)_6]^(3+)` ion is

Options

A. colourless and diamagnetic
B. coloured and octahedral
C. colourless and paramagnetic
D. coloured and paramagnetic

Answer

A

Explanation

`Sc=[Ar]3d^(1) , 4s^2`
Oxidation state of Sc in `[Sc(H_2 O)_6]^(3+)` is `Sc^(3+)`
`Sc^(3+) = [Ar] 3d^0 , 4s^(0)`
Thus `Sc^(3+)` does not have unpaired electron, hence it is diamagnetic and colourless.