Which of the following coordination compounds would exhibit optical isomerism?

Options

A. Pentaamminenitrocobalt (III) iodide
B. Diamminedichloroplatinum (II)
C. Trans-dicyanobis (ethylenediamine) chromium (Ill) chloride
D. Tris-(ethylenediamine) cobalt (III) bromide

Explanation

To determine which of the given coordination compounds exhibit optical isomerism, we need to analyze the structures of each compound and check if their mirror images are superimposable or not. Optical isomerism occurs when a compound has non-superimposable mirror images, meaning they cannot be aligned perfectly with each other.

### Step-by-Step Solution:

1. **Understanding Optical Isomerism**:
- Optical isomerism arises when a compound can exist in two forms that are mirror images of each other but cannot be superimposed. This typically occurs in chiral molecules.

2. **Analyzing Each Compound**:
- **Option A: Pentamino nitro cobalt**:
- Structure: Cobalt is at the center with five amine ligands and one nitro ligand.
- Analysis: The arrangement of ligands does not allow for any asymmetric configuration. The presence of multiple identical amine ligands leads to a symmetrical structure.
- Conclusion: This compound does not exhibit optical isomerism.

- **Option B: Diamine dichloroplatinum**:
- Structure: Platinum is at the center with two amine ligands and two chloride ligands.
- Analysis: The symmetrical arrangement of ligands (either cis or trans) results in superimposable mirror images.
- Conclusion: This compound does not exhibit optical isomerism.

- **Option C: Trans-diamine dicyano**:
- Structure: Platinum is at the center with two cyanide ligands and two ethylene diamine ligands.
- Analysis: The trans configuration leads to a symmetrical arrangement, resulting in superimposable mirror images.
- Conclusion: This compound does not exhibit optical isomerism.

- **Option D: Tris(ethylene diamine) cobalt**:
- Structure: Cobalt is at the center with three ethylene diamine ligands.
- Analysis: The arrangement of three bidentate ethylene diamine ligands creates a chiral environment. The mirror image of this arrangement cannot be superimposed on the original structure.
- Conclusion: This compound exhibits optical isomerism.

3. **Final Answer**:
- The coordination compound that exhibits optical isomerism is **Option D: Tris(ethylene diamine) cobalt**.