According to Fajans'rules, the percentage of covalent character in an ionic compound increase if the cation is highly charged or small in size and the anion is large or cation has pseudoinert gas configuration. As a result of the increased covalent character, solubility in less polar solvent increases and the melting point decreases.
The correct order of increasing ionic character is

Options

A. `BeCl_(2) lt MgCl_(2) lt CaCl_(2) lt BaCl_(2)`
B. `BeCl_(2) lt MgCl_(2) lt BaCl_(2) lt CaCl_(2)`
C. `BeCl_(2) lt BaCl_(2) lt MgCl_(2) lt CaCl_(2)`
D. `BaCl_(2) lt CaCl_(2) lt MgCl_(2) lt BeCl_(2)`

Explanation

To determine the correct order of increasing ionic character according to Fajans' rules, we need to analyze the factors that influence the covalent and ionic character of the compounds involved. Here’s a step-by-step solution:

### Step 1: Understand Fajans' Rules
Fajans' rules state that the covalent character of an ionic compound increases with:
- Higher charge on the cation.
- Smaller size of the cation.
- Larger size of the anion.
- Pseudoinert gas configuration of the cation.

As covalent character increases, ionic character decreases.

**Hint:** Remember that higher charge and smaller size of cations lead to increased covalent character, which inversely affects ionic character.

### Step 2: Identify the Compounds
We are dealing with the chlorides of alkaline earth metals (Group 2), specifically:
- Beryllium chloride (BeCl₂)
- Magnesium chloride (MgCl₂)
- Calcium chloride (CaCl₂)
- Barium chloride (BaCl₂)

**Hint:** List the compounds clearly to analyze their ionic and covalent character.

### Step 3: Analyze the Cations
- Beryllium (Be) has the smallest size and a +2 charge.
- Magnesium (Mg) is larger than Be but still relatively small with a +2 charge.
- Calcium (Ca) is larger than Mg with a +2 charge.
- Barium (Ba) has the largest size with a +2 charge.

As we move down the group, the size of the cation increases, which decreases the covalent character and increases the ionic character.

**Hint:** Compare the sizes of the cations; smaller cations lead to more covalent character.

### Step 4: Determine the Ionic Character Order
Based on the size of the cations:
- **Beryllium chloride (BeCl₂)**: Smallest cation, highest covalent character, lowest ionic character.
- **Magnesium chloride (MgCl₂)**: Larger than Be, lower covalent character, higher ionic character than BeCl₂.
- **Calcium chloride (CaCl₂)**: Larger than Mg, lower covalent character, higher ionic character than MgCl₂.
- **Barium chloride (BaCl₂)**: Largest cation, lowest covalent character, highest ionic character.

Thus, the order of increasing ionic character is:
1. BeCl₂ (lowest ionic character)
2. MgCl₂
3. CaCl₂
4. BaCl₂ (highest ionic character)

**Hint:** Remember that as the size of the cation increases, the ionic character increases.

### Final Answer
The correct order of increasing ionic character is:
**BeCl₂ < MgCl₂ < CaCl₂ < BaCl₂**