Which of the following isomerism is/are shown by the complex `[CoCl_(2)(H_(2)O)_(2)(NH_(3))_(2)]` Br ?

Options

A. Ionization
B. Linkage
C. Geometrical
D. optical

Answer

To determine the types of isomerism shown by the complex \([CoCl_2(H_2O)_2(NH_3)_2]Br\), we will analyze the complex step by step.

### Step 1: Identify the components of the complex
The complex consists of:
- Cobalt (Co) as the central metal atom
- Two chloride ions (Cl)
- Two water molecules (H2O)
- Two ammonia molecules (NH3)
- A bromide ion (Br) outside the coordination sphere

### Step 2: Check for Ionization Isomerism
Ionization isomerism occurs when two isomers have the same composition but yield different ions in solution.

In this case, the complex can release different ions depending on the arrangement of the ligands and the bromide ion. For example, if one of the chloride ions is replaced by the bromide ion, we can have:
1. \([CoCl_2(H_2O)_2(NH_3)_2]^+ + Br^-\) (where one chloride is in the coordination sphere)
2. \([CoCl(H_2O)_2(NH_3)_2Br]^+\) (where bromide is in the coordination sphere)

Since we can have different ions in solution, **ionization isomerism is possible**.

### Step 3: Check for Linkage Isomerism
Linkage isomerism occurs when a ligand can coordinate to the metal in more than one way.

In this complex, the ligands are:
- Chloride (Cl) - a monodentate ligand
- Water (H2O) - a monodentate ligand
- Ammonia (NH3) - a monodentate ligand

None of these ligands can attach to cobalt through different atoms, as they are all monodentate. Therefore, **linkage isomerism is not possible**.

### Step 4: Check for Geometrical Isomerism
Geometrical isomerism occurs in coordination compounds with different spatial arrangements of ligands.

In this case, the complex has the formula type \(MA_2B_2\) (where A = H2O, B = NH3, and M = Co). We can have:
- **Cis isomer**: where the same ligands (H2O or NH3) are adjacent to each other.
- **Trans isomer**: where the same ligands are opposite each other.

Thus, **geometrical isomerism is possible**.

### Step 5: Check for Optical Isomerism
Optical isomerism occurs when a compound can exist in two non-superimposable mirror images.

For optical isomerism to occur, the complex must lack a plane of symmetry. In the case of the cis isomer of the complex, there is no symmetry, meaning it can exist as two enantiomers (non-superimposable mirror images). Therefore, **optical isomerism is possible**.

### Conclusion
The complex \([CoCl_2(H_2O)_2(NH_3)_2]Br\) exhibits:
- Ionization isomerism
- Geometrical isomerism
- Optical isomerism

Thus, the correct options for the types of isomerism shown by this complex are **1 (Ionization), 3 (Geometrical), and 4 (Optical)**.

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