The aqueous solutions of lithlium salts are poor conductor of electricity rather than other alkali metals because of:

Options

A. high ionisation energy
B. high electronegativity
C. lower ability of `Li^(o+)` ions to polaries water molecules
D. higher degree of hydration of `Li^(o+)` ions

Answer

To solve the question regarding why the aqueous solutions of lithium salts are poor conductors of electricity compared to other alkali metals, we can break it down into the following steps:

### Step-by-Step Solution:

1. **Understanding Conductivity in Aqueous Solutions**:
- Conductivity in aqueous solutions is primarily due to the movement of ions. The more mobile the ions are, the better the solution conducts electricity.

2. **Analyzing Alkali Metal Ions**:
- Alkali metals include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr). As we move down the group from lithium to cesium, the size of the alkali metal ions increases.

3. **Degree of Hydration**:
- The degree of hydration refers to how many water molecules surround an ion in solution. Smaller ions tend to have a higher degree of hydration because they can attract more water molecules due to their higher charge density (charge per unit volume).

4. **Lithium Ion Characteristics**:
- Lithium ion (Li⁺) is the smallest among the alkali metal ions. Due to its small size, it has a high charge density, which leads to a higher degree of hydration compared to larger alkali metal ions.

5. **Impact of Hydration on Mobility**:
- The high degree of hydration means that lithium ions are surrounded by a larger number of water molecules. This makes it difficult for the lithium ions to move freely in solution, thus reducing their mobility.

6. **Conclusion on Conductivity**:
- Since the mobility of Li⁺ ions is significantly reduced due to heavy hydration, the conductivity of lithium salts in aqueous solutions is lower compared to other alkali metal salts, which have larger ions and therefore lower degrees of hydration.

### Final Answer:
The aqueous solutions of lithium salts are poor conductors of electricity compared to other alkali metals because of the **higher degree of hydration of lithium ions**, which decreases their mobility in solution.

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