In which of the following pairs both the complexes show geometrical isomerism?

Explanation

To determine which pairs of complexes show geometrical isomerism, we will analyze each option step by step.

### Step 1: Analyze Option 1
- **Complex 1**: [CoCl2(en)2]+
- This complex has two identical ligands (Cl) and two different ligands (en). It can exhibit geometrical isomerism (cis and trans forms).
- **Cis Isomer**: Both Cl ligands are adjacent (90 degrees apart).
- **Trans Isomer**: Cl ligands are opposite each other (180 degrees apart).

- **Complex 2**: [Cr(en)3]3+
- This complex has three identical ligands (en) and does not have any geometrical isomers since all ligands are the same.

**Conclusion**: Only the first complex shows geometrical isomerism. Thus, Option 1 is incorrect.

### Step 2: Analyze Option 2
- **Complex 1**: [CoCl2(NH3)2]
- This complex can also show geometrical isomerism (cis and trans forms).
- **Cis Isomer**: Cl ligands are adjacent (90 degrees apart).
- **Trans Isomer**: Cl ligands are opposite each other (180 degrees apart).

- **Complex 2**: [Co(en)2Cl2]
- This complex can also exhibit geometrical isomerism.
- **Cis Isomer**: Cl ligands are adjacent.
- **Trans Isomer**: Cl ligands are opposite each other.

**Conclusion**: Both complexes show geometrical isomerism. Thus, Option 2 is correct.

### Step 3: Analyze Option 3
- **Complex 1**: [Pt(NH3)(H2O)(Cl)2]
- This complex can show geometrical isomerism.
- **Cis Isomer**: Cl ligands are adjacent.
- **Trans Isomer**: Cl ligands are opposite each other.

- **Complex 2**: [Cr(NH3)3]
- This complex has three identical ligands and does not exhibit geometrical isomerism.

**Conclusion**: Only the first complex shows geometrical isomerism. Thus, Option 3 is incorrect.

### Step 4: Analyze Option 4
- **Complex 1**: [CoCl2(NH3)2]
- This complex can show geometrical isomerism.

- **Complex 2**: [NiCl5]2-
- This complex has five identical ligands and does not exhibit geometrical isomerism.

**Conclusion**: Only the first complex shows geometrical isomerism. Thus, Option 4 is incorrect.

### Final Answer
The correct answer is **Option 2**, as both complexes in this option show geometrical isomerism.