Which of the following ligand gives chelate complexes ?

Options

A. Acelate
B. Oxalate
C. Cyanide
D. Ammonia

Explanation

To determine which ligand gives chelate complexes among the given options, we need to understand the concept of chelation and the types of ligands involved.

### Step-by-Step Solution:

1. **Understanding Chelate Complexes**:
- Chelate complexes are formed when a ligand binds to a metal ion at two or more points, creating a ring structure. This type of bonding is known as chelation.
- Ligands that can form chelate complexes are typically bidentate or polydentate, meaning they have two or more donor atoms that can coordinate with a metal ion.

2. **Identifying the Ligands**:
- We have four ligands to evaluate:
- **Option 1: Acetate (CH₃COO⁻)**
- **Option 2: Oxalate (C₂O₄²⁻)**
- **Option 3: Cyanide (CN⁻)**
- **Option 4: Ammonia (NH₃)**

3. **Analyzing Each Ligand**:
- **Acetate (CH₃COO⁻)**:
- Acetate is a monodentate ligand, meaning it can only coordinate through one atom (the oxygen). Therefore, it cannot form chelate complexes.
- **Oxalate (C₂O₄²⁻)**:
- Oxalate is a bidentate ligand as it has two oxygen atoms that can coordinate with a metal ion. This allows it to form a ring structure with the metal, thus forming a chelate complex.
- **Cyanide (CN⁻)**:
- Cyanide is also a monodentate ligand, coordinating through only one atom (the carbon). It cannot form chelate complexes.
- **Ammonia (NH₃)**:
- Ammonia is a monodentate ligand as it coordinates through the nitrogen atom only. It cannot form chelate complexes.

4. **Conclusion**:
- Among the given options, only **oxalate (Option 2)** can form chelate complexes because it is a bidentate ligand.

### Final Answer:
**Option 2: Oxalate (C₂O₄²⁻)** is the ligand that gives chelate complexes.