For the percipitation reaction of `Ag^(o+)` ions with `NaCI`, which of the following statements is true?

Options

A. `Delta H` for the reaction is zero
B. `Delta G` for the reaction is zero
C. `Delta G` for the reaction is negative
D. `Delta G = Delta H`

Answer

To solve the question regarding the precipitation reaction of `Ag^(o+)` ions with `NaCl`, we need to analyze the statements provided and determine which one is true based on the principles of chemical thermodynamics.

### Step-by-Step Solution:

1. **Identify the Reaction**: The precipitation reaction involves silver ions (`Ag^+`) reacting with sodium chloride (`NaCl`) to form silver chloride (`AgCl`). The balanced chemical equation for this reaction is:
\[ Ag^+ (aq) + Cl^- (aq) \rightarrow AgCl (s) \]

2. **Understand Spontaneity**: A reaction is considered spontaneous if it occurs without needing to be driven by an external force. In thermodynamics, spontaneity is often indicated by the change in Gibbs free energy (ΔG).

3. **Determine Gibbs Free Energy Change**: For a spontaneous reaction, the change in Gibbs free energy (ΔG) must be negative (ΔG < 0). This indicates that the products of the reaction are more stable than the reactants.

4. **Formation of Precipitate**: The formation of a solid precipitate (in this case, `AgCl`) from aqueous ions is a strong driving force for the reaction. The solid precipitate indicates that the system is moving towards a lower energy state, which contributes to the negativity of ΔG.

5. **Conclusion**: Based on the analysis, the statement that is true regarding the precipitation reaction of `Ag^+` ions with `NaCl` is that the change in Gibbs free energy (ΔG) for the reaction is negative.

### Final Answer:
The correct statement is: **ΔG for the reaction is negative (ΔG < 0).**

---