Question

In which of the following pairs both the ions are coloured in aqueous solutions?

• A. \( \text{Sc}^{3+}, \text{Ti}^{3+} \)
• B. \( \text{Ni}^{2+}, \text{Cu}^{2+} \)
• C. \( \text{Sc}^{3+}, \text{Co}^{2+} \)
• D. \( \text{Ni}^{2+}, \text{Ti}^{3+} \)

Hint:

Transition metal ions with partially filled d-orbitals typically form coloured solutions due to electronic transitions.

Answer 1

The Correct Option is D

Both \( \text{Ni}^{2+} \) and \( \text{Ti}^{3+} \) are coloured ions in aqueous solutions, whereas \( \text{Sc}^{3+} \) and \( \text{Cu}^{2+} \) are colourless.

Step 2: Conclusion.
Thus, the correct answer is (4) \( \text{Ni}^{2+}, \text{Ti}^{3+} \).