The correct order of decreasing ionic nature of lead dihalides is

Options

A. `PbI_(2) lt PbBr_(2) lt PbCl_(2) lt PbF_(2)`
B. `PbF_(2) lt PbBr_(2) lt PbCl_(2) lt PbI_(2)`
C. `PbF_(2) lt PbCl_(2) lt PbBr_(2) lt PbI_(2)`
D. `PbF_(2) gt PbCl_(2) gt PbBr_(2) gt PbI_(2)`

Explanation

To determine the correct order of decreasing ionic nature of lead dihalides (PbF2, PbCl2, PbBr2, PbI2), we need to analyze the ionic and covalent character of the compounds based on the size of the anions involved.

### Step-by-Step Solution:

1. **Identify the Compounds**:
We have four lead dihalides:
- PbF2 (Lead(II) fluoride)
- PbCl2 (Lead(II) chloride)
- PbBr2 (Lead(II) bromide)
- PbI2 (Lead(II) iodide)

2. **Understand Ionic vs. Covalent Character**:
- Ionic compounds typically have a high ionic character, which is influenced by the size of the ions involved. Smaller anions tend to lead to a higher ionic character.
- Conversely, larger anions tend to exhibit more covalent character due to decreased charge density.

3. **Compare the Sizes of the Anions**:
- The anions in question are: F⁻ (fluoride), Cl⁻ (chloride), Br⁻ (bromide), and I⁻ (iodide).
- The order of size from smallest to largest is:
- F⁻ < Cl⁻ < Br⁻ < I⁻

4. **Determine Ionic Nature Based on Anion Size**:
- Since F⁻ is the smallest anion, PbF2 will have the highest ionic character.
- Cl⁻ is larger than F⁻, so PbCl2 will have a lower ionic character than PbF2 but higher than the others.
- Br⁻ is larger than Cl⁻, so PbBr2 will have an even lower ionic character.
- I⁻ is the largest anion, so PbI2 will have the lowest ionic character.

5. **Establish the Order of Ionic Nature**:
Based on the analysis, the order of decreasing ionic nature is:
- PbF2 > PbCl2 > PbBr2 > PbI2

6. **Final Answer**:
The correct order of decreasing ionic nature of lead dihalides is:
**PbF2 > PbCl2 > PbBr2 > PbI2**