Which of the following ligands is a bidentate?

Options

A. EDTA
B. Ethylenediamine
C. Acetate
D. Pyridine

Explanation

To determine which of the given ligands is a bidentate ligand, we first need to understand what a bidentate ligand is. A bidentate ligand is a type of ligand that has two donor atoms capable of coordinating to a central metal atom or ion.

### Step-by-Step Solution:

1. **Identify the Ligands**: We need to analyze the given ligands. The ligands mentioned are:
- Ethylene diamine (en)
- Tetraacetate
- Acetate
- Pyridine

2. **Define Bidentate Ligands**: A bidentate ligand has two donor atoms that can bond to a metal center. These donor atoms can be atoms like nitrogen, oxygen, or sulfur that have lone pairs of electrons to donate.

3. **Analyze Each Ligand**:
- **Ethylene Diamine (en)**: The structure of ethylene diamine is NH2-CH2-CH2-NH2. It has two nitrogen atoms that can donate lone pairs, making it a bidentate ligand.
- **Tetraacetate**: Tetraacetate (EDTA) has multiple donor atoms (four oxygen atoms), making it a hexadentate ligand, not bidentate.
- **Acetate**: Acetate (CH3COO-) has one oxygen atom that can donate a lone pair, making it a monodentate ligand.
- **Pyridine**: Pyridine (C5H5N) has one nitrogen atom that can donate a lone pair, making it a monodentate ligand.

4. **Conclusion**: The only ligand that qualifies as a bidentate ligand is **Ethylene Diamine (en)**, as it has two donor nitrogen atoms.

### Final Answer:
The bidentate ligand among the options is **Ethylene Diamine (en)**.

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