What is true about `[EDTA]^(4-)` ?

Options

A. Monodenate ligand
B. Bidenate ligand
C. Quadridentate ligand
D. Hexadentate ligand

Answer

To determine what is true about the EDTA^(4-) ion, we can analyze its structure and properties step by step.

### Step 1: Understanding EDTA Structure
EDTA stands for Ethylenediaminetetraacetic acid. The structure of EDTA consists of two amine groups (–NH2) and four carboxylate groups (–COO^-).

### Step 2: Charge on EDTA
In its fully deprotonated form, EDTA has a charge of -4. This is because each of the four carboxylate groups contributes a -1 charge, while the amine groups are neutral in this form.

### Step 3: Coordination Properties
EDTA is known as a hexadentate ligand. This means it can form six bonds with a metal ion. The two nitrogen atoms from the amine groups and the four oxygen atoms from the carboxylate groups act as donor atoms.

### Step 4: Stability of Complexes
The complexes formed by EDTA with metal ions are typically very stable. EDTA forms octahedral complexes with metal ions due to its ability to wrap around the metal ion, effectively chelating it.

### Step 5: Conclusion
Therefore, the true statements about EDTA^(4-) include:
- It is a hexadentate ligand.
- It can coordinate with metal ions through two nitrogen atoms and four oxygen atoms.
- It forms stable octahedral complexes.

### Final Answer
EDTA^(4-) is a hexadentate ligand that forms stable octahedral complexes with metal ions.

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