JEE Chemistry 2024 Question with Solution

Given: The complex is formed between $\text{Ca}^{2+}$ and $\text{EDTA}^{4-}$.

Find: The coordination environment of $\text{Ca}^{2+}$ in this complex.

Step 1: $\text{EDTA}^{4-}$ is a hexadentate ligand, so it donates through six donor atoms.

Step 2: A metal ion coordinated through six sites forms a six-coordinate complex.

Step 3: Six-coordinate complexes typically have octahedral geometry.

Other options are ruled out because tetrahedral and square planar are generally four-coordinate geometries, while trigonal prismatic is not the usual geometry here.

Therefore, the coordination environment of $\text{Ca}^{2+}$ ion in its complex with $\text{EDTA}^{4-}$ is octahedral. The correct option is B.

Given: $\text{Ca}^{2+}$ forms a complex with $\text{EDTA}^{4-}$.

Find: Which geometry matches the coordination environment.

Analysis:

• Tetrahedral: usually associated with four coordination sites, so it does not fit a hexadentate ligand.
• Octahedral: matches six coordination sites and is the expected geometry for a complex formed by $\text{EDTA}^{4-}$.
• Square planar: also a four-coordinate geometry and not appropriate here.
• Trigonal prismatic: a less common six-coordinate geometry and not the typical environment for this complex.

Since $\text{EDTA}^{4-}$ binds through six donor atoms, the complex is best described as octahedral.

Therefore, the correct option is B.