Consider the follwing complexes ion `P,Q` and `R`
`P =[FeF_(6)]^(3-), Q=[V(H_(2)O)_(6)]^(2+)` and `R=[Fe(H_(2)O)_(6)]^(2+)`
The correct order of the complex ions, according to their spin only magnetic moment values (inBM) is .

Options

A. `R lt Q lt P`
B. `Q lt P lt R`
C. `Q lt R lt P`
D. `R lt P lt Q`

Answer

C

Explanation

`P = [FeF_(6)]^(3-) implies Fe^(3+) (3d^(5)) implies 5` unpaired `bar e` s
`Q = [V(H_(2)O)_(6)]^(2+) implies V^(2+)(3d^(3)) implies 3` unpaired `bar e` s
`R = [Fe(H_(2)O)_(6)]^(2+) implies Fe^(2+) (3d^(6)) 4` unpaired `bar e` s
Since both `F^(-)` and `H_(2)O` are weak field ligands, the no. of unpaired electrons remains unchanged during the formation of complex ion. Thus option (3) is correct.