Which of the following compound of group-14 elements would you expect to be most ionic in character ?

Options

A. `C Cl_(4)`
B. `SiCl_(4)`
C. `PbCl_(2)`
D. `PbCl_(4)`

Answer

To determine which compound of group-14 elements is most ionic in character, we can use Fajan's rule, which helps us understand the covalent and ionic character of compounds based on the properties of their cations and anions.

### Step-by-Step Solution:

1. **Identify the Compounds**: The compounds given in the question are:
- CCl4 (Carbon Tetrachloride)
- SiCl4 (Silicon Tetrachloride)
- PbCl2 (Lead(II) Chloride)
- PbCl4 (Lead(IV) Chloride)

2. **Recognize the Common Anion**: All compounds contain the same anion, Cl⁻ (chloride ion). Thus, we will focus on the cations (the positively charged ions) in each compound.

3. **Analyze the Cations**: The cations present in the compounds are:
- Cation in CCl4: C⁴⁺ (Carbon)
- Cation in SiCl4: Si⁴⁺ (Silicon)
- Cation in PbCl2: Pb²⁺ (Lead)
- Cation in PbCl4: Pb⁴⁺ (Lead)

4. **Apply Fajan's Rule**: According to Fajan's rule, the ionic character of a compound is influenced by:
- **Size of the Cation**: Smaller cations tend to have more covalent character.
- **Charge of the Cation**: Higher charge cations have more covalent character.

5. **Compare Cation Sizes and Charges**:
- C⁴⁺ and Si⁴⁺ are both relatively small and have a +4 charge.
- Pb²⁺ is larger than both C⁴⁺ and Si⁴⁺ but has a lower charge (+2).
- Pb⁴⁺ is larger than C⁴⁺ and Si⁴⁺ and has a +4 charge.

6. **Determine Ionic Character**:
- Since Pb²⁺ has the lowest charge (+2) among the cations, it will exhibit the highest ionic character according to Fajan's rule. The larger size of Pb²⁺ compared to C⁴⁺ and Si⁴⁺ also contributes to its ionic character.

7. **Conclusion**: Therefore, the compound with the most ionic character is **PbCl2** (Lead(II) Chloride).

### Final Answer:
The compound of group-14 elements that would be expected to be most ionic in character is **PbCl2**.