The pair with more ionic nature among lithium halides :-

Options

A. LiF
B. LiCl
C. LiBr
D. LiI

Explanation

To determine the pair with more ionic nature among lithium halides, we need to analyze the ionic character of the lithium halides based on their electronegativity differences. Here’s a step-by-step solution:

### Step-by-Step Solution:

1. **Identify the Lithium Halides**: The lithium halides are lithium fluoride (LiF), lithium chloride (LiCl), lithium bromide (LiBr), and lithium iodide (LiI).

2. **Understand Ionic Character**: Ionic character is influenced by the difference in electronegativity between the metal (lithium) and the non-metal (the halogen). The greater the difference in electronegativity, the more ionic the bond.

3. **Electronegativity Values**: The electronegativity values of the halogens are as follows:
- Fluorine (F): 4.0
- Chlorine (Cl): 3.0
- Bromine (Br): 2.8
- Iodine (I): 2.5

4. **Calculate Electronegativity Differences**: Since lithium has an electronegativity of approximately 1.0, we can calculate the electronegativity differences for each lithium halide:
- For LiF: |1.0 - 4.0| = 3.0
- For LiCl: |1.0 - 3.0| = 2.0
- For LiBr: |1.0 - 2.8| = 1.8
- For LiI: |1.0 - 2.5| = 1.5

5. **Rank the Ionic Character**: Based on the electronegativity differences calculated:
- LiF has the highest difference (3.0), indicating it has the most ionic character.
- LiCl follows with a difference of 2.0.
- LiBr has a difference of 1.8.
- LiI has the lowest difference (1.5), indicating it has the least ionic character.

6. **Conclusion**: The pair with the most ionic nature among the lithium halides is lithium fluoride (LiF), as it has the highest electronegativity difference.

### Final Answer:
The pair with more ionic nature among lithium halides is **LiF (lithium fluoride)**.