Question

Which group contains coloured ions out of

• A. Cu\(^{2+} \)
• B. Co\(^{2+} \)
• C. Fe\(^{2+} \)
• D. Ti\(^{4+} \)

Hint:

The color of metal ions in solutions arises due to electronic transitions in the d-orbitals.

Answer 1

The Correct Option is A

Step 1: Understand the colored ions.
Ions like Cu\(^{2+} \) exhibit a characteristic color due to d-d transitions in the metal ion. Fe\(^{2+} \) also shows color due to similar transitions, but Ti\(^{4+} \) and Co\(^{2+} \) do not exhibit color in their common oxidation states.
Step 2: Conclusion.
Thus, the group containing colored ions is Cu\(^{2+} \).
Final Answer: \[ \boxed{\text{Cu}^{2+}} \]