Which of the following compounds would be most ionic in character ?

Options

A. `PbCl_4`
B. `PbCl_2`
C. `SnCl_4`
D. `SnCl_2`

Answer

To determine which of the given compounds is most ionic in character, we can follow these steps:

### Step 1: Identify the Compounds
Let's assume the four compounds given are:
1. PbCl2 (Lead(II) chloride)
2. SnCl4 (Tin(IV) chloride)
3. SnCl2 (Tin(II) chloride)
4. PbCl4 (Lead(IV) chloride)

### Step 2: Understand Ionic Character
Ionic character in compounds is influenced by the charges of the ions and their polarizing power. According to Fajans' rules, a compound will be more ionic if:
- The charges on the ions are lower.
- The cation has a larger size (lower charge density).
- The cation has a lower polarizing power.

### Step 3: Analyze the Cations
- **Pb2+** (Lead(II)) has a +2 charge.
- **Pb4+** (Lead(IV)) has a +4 charge.
- **Sn2+** (Tin(II)) has a +2 charge.
- **Sn4+** (Tin(IV)) has a +4 charge.

### Step 4: Compare Charges
From the analysis:
- Pb2+ and Sn2+ both have a +2 charge, while Pb4+ and Sn4+ have a +4 charge.
- Higher charges generally lead to greater covalent character due to increased polarizing power.

### Step 5: Assess Polarizing Power
- Sn4+ has a higher polarizing power than Pb4+ due to its smaller size and higher charge.
- Similarly, Sn2+ has a higher polarizing power than Pb2+.

### Step 6: Determine the Most Ionic Compound
- **PbCl2** (Lead(II) chloride) has the lowest charge (+2) and thus is expected to have the most ionic character among the options.
- **SnCl2** (Tin(II) chloride) also has a +2 charge, but Sn2+ has a higher polarizing power than Pb2+.
- **PbCl4** and **SnCl4** both have +4 charges, which leads to greater covalent character.

### Conclusion
Based on the analysis, **PbCl2** is the compound with the most ionic character due to its lower charge and lesser polarizing power compared to the other compounds.

### Final Answer
**PbCl2** is the most ionic compound among the given options.

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