The number of geometrical isomers for octahedral `[CoCl_(4)(NH_(3))_(2)]^(-)`, square planar `[AgBr_(2)Cl_(2)]^(-)` and `[PtCl_(2)(en)]` are:-

Options

A. 2,2,2
B. 2,2,0
C. 3,2,2
D. 2,3,0

Answer

To determine the number of geometrical isomers for the given complexes, we will analyze each compound step by step.

### Step 1: Analyzing the Octahedral Complex \([CoCl_4(NH_3)_2]^-\)

1. **Identify the Geometry**: The complex has an octahedral geometry because it has six ligands surrounding the central cobalt ion.
2. **Ligand Arrangement**: The ligands consist of four chloride ions (Cl) and two ammonia molecules (NH₃).
3. **Possible Isomer Configurations**:
- **Cis Isomer**: Both NH₃ ligands are adjacent to each other.
- **Trans Isomer**: The NH₃ ligands are opposite each other.
4. **Count the Isomers**:
- There are 1 cis and 1 trans arrangement.
- **Total Isomers**: 2 (1 cis + 1 trans).

### Step 2: Analyzing the Square Planar Complex \([AgBr_2Cl_2]^-\)

1. **Identify the Geometry**: The complex has a square planar geometry due to the arrangement of four ligands around the silver ion.
2. **Ligand Arrangement**: The ligands consist of two bromide ions (Br) and two chloride ions (Cl).
3. **Possible Isomer Configurations**:
- **Cis Isomer**: Both Br ligands are adjacent to each other.
- **Trans Isomer**: The Br ligands are opposite each other.
4. **Count the Isomers**:
- There are 1 cis and 1 trans arrangement.
- **Total Isomers**: 2 (1 cis + 1 trans).

### Step 3: Analyzing the Complex \([PtCl_2(en)]\)

1. **Identify the Geometry**: The complex has an octahedral geometry since it has two chloride ions and one bidentate ligand (ethylenediamine, en).
2. **Ligand Arrangement**: The ethylenediamine ligand occupies two coordination sites, while the two chloride ions occupy the remaining sites.
3. **Possible Isomer Configurations**:
- Since the ethylenediamine is bidentate, it cannot create geometrical isomers because it occupies two adjacent positions in the octahedral arrangement.
4. **Count the Isomers**:
- There are no possible cis or trans arrangements due to the nature of the bidentate ligand.
- **Total Isomers**: 0.

### Final Summary of Isomers
- For \([CoCl_4(NH_3)_2]^-\): 2 isomers (1 cis + 1 trans).
- For \([AgBr_2Cl_2]^-\): 2 isomers (1 cis + 1 trans).
- For \([PtCl_2(en)]\): 0 isomers.

### Final Answer
- The number of geometrical isomers for the three complexes are:
- \([CoCl_4(NH_3)_2]^-\): 2
- \([AgBr_2Cl_2]^-\): 2
- \([PtCl_2(en)]\): 0

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