Which of the following ions is the most stable in aqueous solution ?
`(At . No . Ti = 22, V = 23, Cr = 24, Mn = 25)`

Options

A. `Cr^(3+)`
B. `V^(3+)`
C. `Ti^(3+)`
D. `Mn^(3+)`

Answer

D

Explanation

Stability of transition metal ion is directly proportional to the unpaired electrons, the exactly half-filled and completely filled d-orbitals are extra stable.
`Cr^(3+)` (21)= `3d^(3)` `4s^(0) - 3` unpaired electrons
`V^(3+) (20)=3d^(2) 4s^(0) -2` unpaired electrons
`Ti^(3+) (19) = 3d^(1) 4s^(0) - 1` unpaired electron
`Mn^(3+) (22)=3d^(4) 4s^(0) - 4` unpaired electrons
So, `Mn^(3+)` ion is most stable in aqueous solution.