The lattice energy of NaCl is 788 kJ `mol^(-1)` . This means that 788 kJ of energy is required

Options

A. to separate one mole of solid NaCl into one mole of `Na_((g))` and one mole of `Cl_((g))` to infinite distance
B. to separate one mole of solid NaCl into one mole of `Na_((g))^(+)` and one mole of `Cl_((g))^(-)` to infinite distance
C. to convert one mole of solid NaCl into one mole of gaseous NaCl
D. to convert one mole of gaseous NaCl into one mole of solid NaCl.

Explanation

To solve the question regarding the lattice energy of NaCl, we will follow these steps:

### Step-by-Step Solution:

1. **Understanding Lattice Energy**:
Lattice energy is defined as the amount of energy required to separate one mole of an ionic solid into its gaseous ions.

2. **Identifying the Given Data**:
We are given that the lattice energy of NaCl is 788 kJ/mol. This means that to break down one mole of NaCl solid into its constituent ions, 788 kJ of energy is needed.

3. **Writing the Dissociation Reaction**:
The dissociation of solid NaCl can be represented by the following equation:
\[ \text{NaCl (s)} \rightarrow \text{Na}^+ (g) + \text{Cl}^- (g) \]
This reaction shows that one mole of solid NaCl dissociates into one mole of sodium ions and one mole of chloride ions in the gaseous state.

4. **Analyzing the Options**:
We need to evaluate the provided options based on the definition of lattice energy and the dissociation reaction:
- Option A: Incorrect, as it mentions chlorine gas instead of chloride ions.
- Option B: Correct, as it accurately describes the separation of NaCl into sodium ions and chloride ions.
- Option C: Incorrect, as it suggests converting solid NaCl into gaseous NaCl, which is not the definition of lattice energy.
- Option D: Incorrect, as it suggests converting gaseous NaCl back to solid NaCl, which also does not represent lattice energy.

5. **Conclusion**:
Based on the analysis, the correct interpretation of the lattice energy of NaCl is that it is the energy required to separate one mole of solid NaCl into one mole of sodium ions and one mole of chloride ions at infinite distance. Therefore, the correct answer is Option B.