Which has the maximum covalent character?

Options

A. `MgCl_(2)`
B. NaCl
C. `SiCl_(4)`
D. `AlCl_(3)`

Explanation

To determine which compound has the maximum covalent character among the given chlorides, we can use Fajans' rules, which help us understand the covalent character in ionic compounds. Here’s a step-by-step solution:

### Step 1: Understand Fajans' Rules
Fajans' rules state that the covalent character of an ionic compound depends on two main factors:
1. **Polarizing Power of the Cation**: This is the ability of the cation to distort the electron cloud of the anion. It is influenced by:
- The charge of the cation: Higher charge means greater polarizing power.
- The size of the cation: Smaller size means greater polarizing power.

2. **Polarizability of the Anion**: This is the ability of the anion's electron cloud to be distorted. It is influenced by:
- The charge of the anion: Higher charge means greater polarizability.
- The size of the anion: Larger size means greater polarizability.

### Step 2: Analyze the Given Options
We need to analyze the cations in the given chlorides:
- **A. MgCl₂**: Magnesium (Mg) has a +2 charge.
- **B. NaCl**: Sodium (Na) has a +1 charge.
- **C. SiCl₄**: Silicon (Si) has a +4 charge.
- **D. AlCl₃**: Aluminum (Al) has a +3 charge.

### Step 3: Determine Polarizing Power
Based on the charges:
- Mg²⁺ (charge +2)
- Na⁺ (charge +1)
- Si⁴⁺ (charge +4)
- Al³⁺ (charge +3)

The polarizing power increases with the charge of the cation. Thus, Si⁴⁺ has the highest polarizing power among the given cations.

### Step 4: Conclusion
Since SiCl₄ has the highest charge on its cation (+4), it will have the maximum covalent character compared to the other chlorides.

### Final Answer
The compound with the maximum covalent character is **C. SiCl₄**.

---