AIIMS 2019 Chemistry Properties of Compounds MCQ Question

The pale yellow color of bismuth carbonate (Bi₂(CO₃)₃) is attributed to the presence of Bi³⁺ ions, which exhibit color due to their electronic transitions. In contrast, the carbonates of Hg₂²⁺, Sr²⁺, and Li⁺ are colorless because these metal ions do not have unpaired d-electrons, preventing any electronic transitions that would result in color. This distinction highlights the role of electronic structure in determining the color of metal carbonates.