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.