Which of the following is a flexidentate ligand?

Options

A. `H_(2)O`
B. EDTA
C. `CI^(-)`
D. `NO_(2)^(-)`

Answer

To determine which of the following is a flexidentate ligand, we need to understand the definition and characteristics of flexidentate ligands, as well as analyze the options provided.

### Step-by-Step Solution:

1. **Understanding Flexidentate Ligands**:
- Flexidentate ligands are those ligands that can bind to a metal ion through different donor atoms in different coordination complexes. This means that they can exhibit different denticities (number of donor atoms) depending on the metal ion they are coordinated with.

2. **Identifying the Options**:
- We need to evaluate the ligands given in the options. Common examples of ligands include water (H2O), ethylenediamine (en), EDTA, chloride ion (Cl-), and nitrite ion (NO2-).

3. **Analyzing Each Ligand**:
- **Water (H2O)**: It has only one donor atom (oxygen), making it a monodentate ligand. It cannot change its denticity.
- **Chloride Ion (Cl-)**: Similar to water, it has only one donor atom and is also a monodentate ligand.
- **Nitrite Ion (NO2-)**: Although it has two potential donor atoms (N and O), it can only bind through one at a time, making it effectively a monodentate ligand.
- **EDTA (Ethylenediaminetetraacetic acid)**: This ligand can bind through multiple donor atoms (two nitrogen and four oxygen atoms), allowing it to act as a hexadentate ligand. However, it can also exhibit different denticities (like pentadentate or tetradentate) depending on the metal ion it coordinates with.

4. **Conclusion**:
- Among the options analyzed, EDTA is the only ligand that can change its denticity based on the metal it coordinates with, making it a flexidentate ligand.

### Final Answer:
**EDTA (Ethylenediaminetetraacetic acid) is a flexidentate ligand.**

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