Anhydrous `AlCl_3` is covalent compound. Select the correct statement regarding `AlCl_3` based on the given information. Given, the energy to ionise `AlCl_3` is 5215 kJ `mol^-1` , `Delta_Hydration ` for `Al^(3+) ` is -4670 kJ `mol^-1` and `Delta_Hydration ` for `Cl^-` is -381 kJ `mol^-1`

Options

A. It will remain covalent
B. It will remain ionic
C. It may or may not be ionic
D. Any molecule being ionic or covalent is independent of ionisation energy

Answer

To analyze the properties of anhydrous \( \text{AlCl}_3 \) and determine the correct statement regarding it, we can follow these steps:

### Step 1: Understand the Given Data
We have the following information:
- Ionization energy of \( \text{AlCl}_3 \): \( 5215 \, \text{kJ/mol} \)
- Hydration energy for \( \text{Al}^{3+} \): \( -4670 \, \text{kJ/mol} \)
- Hydration energy for \( \text{Cl}^{-} \): \( -381 \, \text{kJ/mol} \)

### Step 2: Calculate Total Hydration Energy
To find the total hydration energy when \( \text{AlCl}_3 \) dissolves in water, we need to account for the hydration of one \( \text{Al}^{3+} \) ion and three \( \text{Cl}^{-} \) ions.

\[ \text{Total Hydration Energy} = \Delta H_{\text{hydration}}(\text{Al}^{3+}) + 3 \times \Delta H_{\text{hydration}}(\text{Cl}^{-}) \]

Substituting the values:

\[ \text{Total Hydration Energy} = -4670 \, \text{kJ/mol} + 3 \times (-381 \, \text{kJ/mol}) \]

Calculating the contribution from the chloride ions:

\[ 3 \times (-381) = -1143 \, \text{kJ/mol} \]

Now, adding these values together:

\[ \text{Total Hydration Energy} = -4670 - 1143 = -5813 \, \text{kJ/mol} \]

### Step 3: Compare Ionization Energy and Hydration Energy
Now, we compare the ionization energy with the total hydration energy:

- Ionization energy: \( 5215 \, \text{kJ/mol} \)
- Total hydration energy: \( -5813 \, \text{kJ/mol} \)

### Step 4: Analyze the Result
The total hydration energy is negative, indicating that energy is released when \( \text{AlCl}_3 \) dissolves in water. The ionization energy is positive, indicating that energy is required to ionize \( \text{AlCl}_3 \).

### Conclusion
Since the absolute value of the total hydration energy (\( 5813 \, \text{kJ/mol} \)) is greater than the ionization energy (\( 5215 \, \text{kJ/mol} \)), this suggests that the process of dissolving \( \text{AlCl}_3 \) is energetically favorable. Therefore, the correct statement regarding \( \text{AlCl}_3 \) is that it has significant covalent character due to the large difference in hydration energy compared to ionization energy.