Question

Which of these ions is expected to be coloured in aqueous solution?

• A. Fe\(^{3+} \)
• B. Ni\(^{2+} \)
• C. Al\(^{3+} \)
• D. I and III

Hint:

Transition metal ions with unfilled d-orbitals can show color due to d-d transitions when placed in a solution.

Answer 1

The Correct Option is A

Step 1: Color of ions in solution.
Transition metal ions such as \( \text{Fe}^{3+} \) often exhibit color in solution due to d-d transitions, whereas ions like \( \text{Ni}^{2+} \) and \( \text{Al}^{3+} \) do not show such color.

Step 2: Conclusion.
The \( \text{Fe}^{3+} \) ion is expected to be colored in solution, corresponding to option (1).