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 solve the problem regarding the nature of anhydrous AlCl₃ (aluminum chloride) based on the provided information, we will follow these steps:

### Step 1: Understand the Given Data
We are given:
- Ionization energy of AlCl₃: **5215 kJ/mol**
- Hydration enthalpy for Al³⁺: **-4670 kJ/mol**
- Hydration enthalpy for Cl⁻: **-381 kJ/mol**

### Step 2: Calculate the Total Hydration Enthalpy for AlCl₃
Since AlCl₃ consists of one Al³⁺ ion and three Cl⁻ ions, we need to calculate the total hydration enthalpy for AlCl₃.

1. **Hydration enthalpy for Al³⁺**:
\[ \Delta H_{\text{hydration, Al}^{3+}} = -4670 \text{ kJ/mol} \]

2. **Hydration enthalpy for 3 Cl⁻ ions**:
\[ \Delta H_{\text{hydration, 3 Cl}^-} = 3 \times (-381 \text{ kJ/mol}) = -1143 \text{ kJ/mol} \]

3. **Total hydration enthalpy for AlCl₃**:
\[ \Delta H_{\text{hydration, AlCl}_3} = \Delta H_{\text{hydration, Al}^{3+}} + \Delta H_{\text{hydration, 3 Cl}^-} \]
\[ \Delta H_{\text{hydration, AlCl}_3} = -4670 \text{ kJ/mol} + (-1143 \text{ kJ/mol}) = -5813 \text{ kJ/mol} \]

### Step 3: Compare Hydration Enthalpy and Ionization Energy
Now, we compare the magnitudes of the hydration enthalpy and the ionization energy:

- **Ionization energy**: **5215 kJ/mol**
- **Hydration enthalpy**: **5813 kJ/mol**

### Step 4: Analyze the Results
Since the magnitude of the hydration enthalpy (-5813 kJ/mol) is greater than the ionization energy (5215 kJ/mol), it indicates that the energy released during hydration is greater than the energy required to ionize AlCl₃. Thus, when AlCl₃ is dissolved in water, it will favor the formation of ions.

### Conclusion
Based on the analysis, when anhydrous AlCl₃ is treated with water, it will dissociate into ions, confirming that it will become ionic in nature.

### Final Answer
**It will remain ionic.**

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