Which kind of isomerism is exhibited by octahedral `[Co(NH_(3))_(4)Br_(2)]CI` ? .

Options

A. Geometrical and ionization
B. Geometrical and optical
C. Optical and ionization
D. Geometrical only

Answer

To determine the kind of isomerism exhibited by the octahedral complex \([Co(NH_3)_4Br_2]Cl\), we can follow these steps:

### Step 1: Identify the Coordination Complex
The given complex is \([Co(NH_3)_4Br_2]Cl\). It consists of a cobalt (Co) ion coordinated with four ammonia (NH₃) ligands and two bromide (Br) ligands, with a chloride (Cl) ion as a counter ion.

**Hint:** Look for the central metal ion and the ligands attached to it.

### Step 2: Determine the Geometry
The complex has an octahedral geometry because it consists of six coordination sites around the cobalt ion (4 from NH₃ and 2 from Br).

**Hint:** Recall that octahedral complexes have 6 ligands arranged around the central metal ion.

### Step 3: Analyze Possible Isomerism
1. **Ionization Isomerism**: This occurs when the composition of the ions in solution differs. For example, if one of the bromide ions is replaced by a chloride ion in the coordination sphere, it would lead to different ions in solution.

2. **Geometrical Isomerism**: In octahedral complexes, geometrical isomers can exist in cis and trans forms. The cis form has similar ligands adjacent to each other, while in the trans form, they are opposite.

**Hint:** Consider how the ligands are arranged around the central metal ion.

### Step 4: Identify the Types of Isomers
- **Ionization Isomer**: \([Co(NH_3)_4Br_2]Cl\) can have an ionization isomer where the bromide ion is outside the coordination sphere, leading to a different ion composition in solution.

- **Geometrical Isomers**: The complex can exist in cis and trans forms:
- **Cis Isomer**: Both bromide ions are adjacent to each other.
- **Trans Isomer**: The bromide ions are opposite each other.

**Hint:** Visualize the arrangement of ligands to distinguish between cis and trans configurations.

### Step 5: Determine Optical Isomerism
- **Optical Isomerism**: This occurs when a compound can exist in two non-superimposable mirror images. The cis form can be optically active, while the trans form is not, as it can be superimposed on its mirror image.

**Hint:** Check if the arrangement of ligands allows for non-superimposable mirror images.

### Conclusion
The complex \([Co(NH_3)_4Br_2]Cl\) exhibits **geometrical isomerism** (cis and trans forms) and **ionization isomerism** (due to the presence of different ions in solution). Therefore, the answer to the question is:

**Answer**: The complex exhibits geometrical isomerism and ionization isomerism.