Which of the following cannot act as an electrolyte

Options

A. `CoCl_(3).6NH_(3)`
B. `CoCl_(3).5NH_(3)`
C. `CoCl_(3).4NH_(3)`
D. `CoCl_(3).3NH_(3)`

Answer

To determine which of the given compounds cannot act as an electrolyte, we need to analyze the coordination complexes formed by each compound and their ability to dissociate into ions when dissolved in water.

### Step-by-Step Solution:

1. **Understanding Electrolytes**:
- Electrolytes are substances that dissociate into ions when dissolved in water. This dissociation allows them to conduct electricity.

2. **Analyzing the Given Compounds**:
- The compounds provided are:
- COCl3·6NH3
- COCl3·5NH3
- COCl3·4NH3
- COCl3·3NH3

3. **Examining Each Compound**:
- **COCl3·6NH3**:
- This compound can form a complex ion [Co(NH3)6]Cl3. It can dissociate into [Co(NH3)6]³⁺ and 3Cl⁻ ions in solution. Thus, it can act as an electrolyte.

- **COCl3·5NH3**:
- This compound forms [Co(NH3)5]Cl2. It can dissociate into [Co(NH3)5]²⁺ and 2Cl⁻ ions. Hence, it can also act as an electrolyte.

- **COCl3·4NH3**:
- This forms [Co(NH3)4]Cl2. It can dissociate into [Co(NH3)4]²⁺ and 2Cl⁻ ions. Therefore, it can act as an electrolyte.

- **COCl3·3NH3**:
- This compound forms [Co(NH3)3] with no chloride ions outside the coordination sphere. It does not have any anions to dissociate into, meaning it cannot produce ions in solution.

4. **Conclusion**:
- Among the given options, COCl3·3NH3 is the only compound that cannot act as an electrolyte because it does not dissociate into ions when dissolved in water.

### Final Answer:
- The compound that cannot act as an electrolyte is **COCl3·3NH3**.