Which of the following will not conduct electricity ?

Options

A. `K^(+)Cl^(-)` (Aqueous solution)
B. `K^(+)Cl^(-)` (Solid state)
C. `Na^(+)Cl^(-)` (Fused state)
D. Graphite

Explanation

To determine which of the given options will not conduct electricity, we can analyze each option based on the state of the substance and the presence of ions or free electrons.

### Step-by-Step Solution:

1. **Option 1: K⁺ Cl⁻ (aqueous)**
- In this option, potassium ions (K⁺) and chloride ions (Cl⁻) are in an aqueous solution.
- **Reasoning**: In an aqueous solution, ions are free to move. The presence of free-moving ions allows the solution to conduct electricity.
- **Conclusion**: This option **will conduct electricity**.

2. **Option 2: K⁺ Cl⁻ (solid state)**
- Here, K⁺ and Cl⁻ are in a solid state.
- **Reasoning**: In solid form, the ions are fixed in a lattice structure and cannot move freely. Without the movement of ions, there is no conduction of electricity.
- **Conclusion**: This option **will not conduct electricity**.

3. **Option 3: Na⁺ Cl⁻ (fused state)**
- In this case, Na⁺ and Cl⁻ are in a fused (molten) state.
- **Reasoning**: In the fused state, the ionic compound is melted, allowing the ions to move freely. This mobility of ions enables the conduction of electricity.
- **Conclusion**: This option **will conduct electricity**.

4. **Option 4: Graphite**
- Graphite is a form of carbon that has a layered structure.
- **Reasoning**: In graphite, there are delocalized electrons (free electrons) due to the sp² hybridization of carbon atoms. These free electrons can move and carry charge, allowing graphite to conduct electricity, albeit weakly.
- **Conclusion**: This option **will conduct electricity** (though it is a poor conductor).

### Final Answer:
The option that will **not conduct electricity** is **Option 2: K⁺ Cl⁻ in solid state**.