`[EDTA]^(4-)` is a

Options

A. Monodentate ligand
B. Bidentate ligand
C. Quadridentate ligand
D. Hexadentate ligand

Explanation

To determine the nature of the ligand `[EDTA]^(4-)`, we can follow these steps:

### Step 1: Identify the Structure of EDTA
EDTA stands for Ethylenediaminetetraacetic acid. Its structure consists of two amine groups and four acetic acid groups.

### Step 2: Determine the Charge of EDTA
EDTA has a total charge of -4. This is because the four acetic acid groups can each donate a negative charge when they lose a proton (H^+).

### Step 3: Classify EDTA as a Ligand
EDTA is classified as a chelating ligand because it can bind to a metal ion at multiple sites. It has multiple donor atoms (two nitrogen atoms and four oxygen atoms from the acetic acid groups).

### Step 4: Count the Donor Atoms
In total, EDTA can donate six pairs of electrons to a metal ion:
- 2 from the nitrogen atoms
- 4 from the oxygen atoms (one from each acetic acid group)

### Step 5: Conclusion
Thus, `[EDTA]^(4-)` is a hexadentate ligand, meaning it can coordinate to a metal ion at six sites.

---