The complexes `[Co(NH_3)_4(H_2O)Cl] Br_2 and [Co(NH_3)_4Br_2]Cl.H_2O` are examples of

Options

A. ionization isomerism
B. linkage isomerism
C. geometrical isomerism
D. optical isomerism

Answer

To solve the question regarding the complexes \([Co(NH_3)_4(H_2O)Cl] Br_2\) and \([Co(NH_3)_4Br_2]Cl.H_2O\), we need to identify the type of isomers they represent.

### Step-by-Step Solution:

1. **Identify the Complexes**:
- The first complex is \([Co(NH_3)_4(H_2O)Cl] Br_2\).
- The second complex is \([Co(NH_3)_4Br_2]Cl.H_2O\).

2. **Analyze the Composition**:
- Both complexes contain the same metal ion (Co), the same ligands (NH3, H2O, Cl, Br), but they differ in the arrangement of these ligands and the position of the counter ions (Br and Cl).

3. **Understand Ionization Isomers**:
- Ionization isomers are those that differ in the ion that is released when the complex is dissolved in water. This occurs when the ligands or counter ions are arranged differently, leading to the formation of different ions in solution.

4. **Determine the Ions Produced**:
- For the first complex \([Co(NH_3)_4(H_2O)Cl] Br_2\):
- When dissolved, it can produce \(Co(NH_3)_4(H_2O)Cl^{2+}\) and \(2Br^{-}\).
- For the second complex \([Co(NH_3)_4Br_2]Cl.H_2O\):
- When dissolved, it can produce \(Co(NH_3)_4Br_2^{+}\) and \(Cl^{-}\) along with \(H_2O\) as a crystallization water.

5. **Conclusion**:
- Since the two complexes yield different ions when dissolved in water, they are classified as **ionization isomers**.

### Final Answer:
The complexes \([Co(NH_3)_4(H_2O)Cl] Br_2\) and \([Co(NH_3)_4Br_2]Cl.H_2O\) are examples of **ionization isomers**.