Optical isomerism is exhibited by (ox = oxalate anion, en = ethylene diamine)

Options

A. `cis-[CrCl_(2)(o x)_(2)]^(3-)`
B. `[Co(en)_(3)]^(3+)`
C. trans-`[CrCl_(2)(o x)_(2)]^(3-)`
D. `[Co(o x)(en)_(2)]^(+)`

Explanation

To determine which coordination compound exhibits optical isomerism involving oxalate anion (ox) and ethylene diamine (en), we will follow these steps:

### Step 1: Understand Optical Isomerism
Optical isomerism occurs when a compound can exist in two non-superimposable mirror images, known as enantiomers. This typically requires the presence of a chiral center, which is often found in coordination compounds with specific geometries.

**Hint:** Look for coordination compounds that lack a plane of symmetry and have chiral centers.

### Step 2: Identify the Coordination Compounds
Consider the coordination compounds that can be formed with oxalate and ethylene diamine. For example:
- [Co(en)2(ox)]²⁻
- [Co(ox)2(en)₂]²⁻

**Hint:** Write down the possible coordination compounds using the ligands provided.

### Step 3: Analyze the Geometries
- Ethylene diamine (en) is a bidentate ligand, meaning it can form two bonds with the metal center.
- Oxalate (ox) is also a bidentate ligand.

When these ligands coordinate with a metal like cobalt (Co), they can create different geometrical arrangements.

**Hint:** Determine the coordination number and geometry of the complexes formed.

### Step 4: Check for Chirality
For the complex [Co(en)2(ox)]²⁻:
- The arrangement of the bidentate ligands can lead to a chiral complex since the two en ligands can be arranged in such a way that they create a non-superimposable mirror image.

For the complex [Co(ox)2(en)₂]²⁻:
- This complex may have a plane of symmetry due to the symmetrical arrangement of the oxalate ligands, which could prevent optical isomerism.

**Hint:** Visualize the 3D structure of the complexes to see if they can exist as non-superimposable mirror images.

### Step 5: Conclusion
Based on the analysis, the complex [Co(en)2(ox)]²⁻ exhibits optical isomerism due to its chiral arrangement, while [Co(ox)2(en)₂]²⁻ does not exhibit optical isomerism.

**Final Answer:** The coordination compound that exhibits optical isomerism is [Co(en)2(ox)]²⁻.