In which of the following paris both the ions are coloured in aqueous solution? (Atomic number, `Sc - 21, Ti = 22, Ni = 28, Cu = 29, Co = 27)`

Options

A. `Sc^(3+), Co^(2+)`
B. `Ni^(2+), Cu^(+)`
C. `Ni^(2+), Ti^(3+)`
D. `Sc^(3+), Ti^(3+)`

Answer

C

Explanation

`Sc^(3+) rArr` no unpaired electron
`Ca^(+) rArr` no unpaired electron
`Cu^(+) rArr` no unpaired electron
`Ni^(2+) rArr `2 unpaired electrons
`Ti^(3+) rArr` 1 unpaired electron