The pair in which both species have same magnetic moment (spin only value) is .

Options

A. `|Cr(H_(2)O)|^(2+), |CoCl_(4)|^(2-)`
B. `|Cr(H_(2)O)_(6)|^(2+), |Fe(OH)_(6)|^(2+)`
C. `[Mn(H_(2)O)_(6)]^(2+), |Cr(H_(2)O)_(6)|^(2+)`
D. `|CoCl_(4)|^(2-), |Fe(H_(2)O)_(6)|^(2+)`

Answer

B

Explanation

`mu = sqrt(n(n+2))`
(n)are
`Cl^(2+) (3d^(4)), n = 4 , Co^(2+) (3d^(7)), n = 3`
`Fe^(2+) (3d^(6)), n = 4 , Mn^(2+) (3d^(5)), n = 5`
Thus `Cr^(2+) and Fe^(2+)` have same number of unpaired electrons. Hence in pair (B), both species will have same magnetic moment.