Question

Which of the following set has all the colored ions?

• A. $C{u}^{+},C{u}^{2+},N{i}^{2+}$
• B. $C{u}^{2+},C{O}^{2+},S{c}^{3+}$
• C. $C{u}^{2+},F{e}^{2+},C{O}^{2+}$
• D. $N{a}^{+},M{g}^{2+},A{l}^{3+}$

Answer 1

Answer: (C)

Species having unpaired electrons in d-orbitals, allow d-d transition, hence are colored.
Hence, $C{u}^{2+},F{e}^{2+}$ and $C{o}^{2+}$ constituate a set of coloured ions.