Concentrated `H_(2)SO_(4)` will not dehydrate the following complex:

Options

A. `[Cr(H_(2)O)_(5)Cl]Cl_(2).H_(2)O`
B. `[Cr(H_(2)O)_(4)Cl_(2)]Cl.2H_(2)O`
C. `[Cr(H_(2)O)_(6)]Cl_(6)`
D. All of these

Answer

To solve the question regarding which complex will not be dehydrated by concentrated H₂SO₄, we need to analyze the given coordination complexes and their components.

### Step-by-Step Solution:

1. **Understand Coordination Complexes**:
- A coordination complex consists of a central metal atom or ion surrounded by ligands. The entire assembly is enclosed in square brackets, known as the coordination sphere. Any ions outside the brackets are called counter ions.

2. **Identify the Given Complexes**:
- The complexes provided are:
1. [Cr(H₂O)₅Cl]Cl₂H₂O
2. [Cr(H₂O)₄Cl₂]Cl₂H₂O
3. [Cr(H₂O)₆]Cl₆

3. **Analyze Each Complex**:
- **Complex 1**: [Cr(H₂O)₅Cl]Cl₂H₂O
- Coordination Sphere: [Cr(H₂O)₅Cl]
- Ionization Sphere: Cl₂H₂O
- When treated with concentrated H₂SO₄, one water molecule from the ionization sphere can be removed, leading to dehydration.

- **Complex 2**: [Cr(H₂O)₄Cl₂]Cl₂H₂O
- Coordination Sphere: [Cr(H₂O)₄Cl₂]
- Ionization Sphere: Cl₂H₂O
- Two water molecules can be removed from the ionization sphere when treated with concentrated H₂SO₄, allowing for dehydration.

- **Complex 3**: [Cr(H₂O)₆]Cl₆
- Coordination Sphere: [Cr(H₂O)₆]
- Ionization Sphere: Cl₆ (no water molecules)
- Since there are no water molecules in the ionization sphere, concentrated H₂SO₄ cannot extract any water from this complex. Therefore, no dehydration occurs.

4. **Conclusion**:
- The complex that will not be dehydrated by concentrated H₂SO₄ is **[Cr(H₂O)₆]Cl₆**.

### Final Answer:
The complex that will not be dehydrated by concentrated H₂SO₄ is **[Cr(H₂O)₆]Cl₆**.