The correct order of equivalent conductance at infinite dilution of LiCI, NaCI and KCI is

Options

A. LiCI gt NaCI gt KCI
B. KCI gt NaCI gt LiCI
C. NaCI gt KCI gt LiCI
D. LiCI gt KCI gt NaCI

Answer

To determine the correct order of equivalent conductance at infinite dilution of LiCl, NaCl, and KCl, we need to analyze the factors affecting ionic conductance.

### Step-by-Step Solution:

1. **Understanding Equivalent Conductance**:
Equivalent conductance (Λ) at infinite dilution refers to the conductance of all ions in solution when they are completely separated. It is influenced by the mobility of the ions.

2. **Analyzing the Cations**:
The compounds in question (LiCl, NaCl, KCl) all have the same anion (Cl⁻) but different cations (Li⁺, Na⁺, K⁺). The charge on these cations is the same (+1), but their sizes differ.

3. **Ionic Size and Hydration**:
As we move down the alkali metal group in the periodic table from Li to Na to K, the ionic radius increases. This means:
- Li⁺ < Na⁺ < K⁺ (in terms of size).
- Smaller cations (like Li⁺) have a higher degree of hydration because they can attract water molecules more strongly due to their higher charge density.

4. **Degree of Solvation**:
The degree of solvation decreases as the size of the cation increases. Therefore:
- Li⁺ is heavily hydrated, leading to a larger hydrated radius.
- Na⁺ is moderately hydrated.
- K⁺ is the least hydrated.

5. **Ionic Mobility**:
The mobility of ions in solution is inversely related to their hydrated size. Smaller hydrated ions move more freely:
- Li⁺ has a larger hydrated radius and thus lower mobility.
- Na⁺ has moderate mobility.
- K⁺, being the largest, has the smallest hydrated radius and therefore the highest mobility.

6. **Conductance Order**:
Since the mobility of the ions is highest for K⁺, followed by Na⁺, and lowest for Li⁺, we can conclude:
- KCl > NaCl > LiCl in terms of equivalent conductance at infinite dilution.

### Final Order:
The correct order of equivalent conductance at infinite dilution is:
**KCl > NaCl > LiCl**