Question

Which of the following pairs of aquated first transition metal ions have the same color?

• A. $Cr^{3+}, Mn^{3+}$
• B. $Ti^{3+}, Cu^{2+}$
• C. $Fe^{2+}, Co^{2+}$
• D. $Fe^{2+}, Cu^{2+}$
• E. $Fe^{3+}, Co^{3+}$

Hint:

The colors of transition metal ions arise from d-d transitions in the presence of ligands.

Answer 1

The Correct Option is A

Step 1: The color of transition metal ions depends on electronic configuration and ligand field effects. 
Step 2: - $Cr^{3+}$ and $Mn^{3+}$ both exhibit purple/violet colors in aqueous solutions. 
- Other pairs exhibit different colors due to differences in d-orbital splitting. 
Step 3: Therefore, the correct answer is (A).