which one of the following aqueous solution of salts has the lowest pH value?

Options

A. `CH_(3) COONa`
B. `NaCI`
C. `NH_(4)OOCCH_(3)`
D. `NH_(4)CI`

Answer

To determine which aqueous solution of salts has the lowest pH value, we need to analyze the nature of each salt and how they dissociate in water. The pH of a solution is inversely related to the concentration of hydrogen ions (H⁺) present in the solution. The more H⁺ ions present, the lower the pH.

### Step-by-Step Solution:

1. **Understand the Concept of pH**:
- pH is defined as \( \text{pH} = -\log[H^+] \).
- A lower pH indicates a higher concentration of H⁺ ions.

2. **Identify the Salts Given**:
- Let's consider the salts provided in the question (not explicitly listed, but we can assume common examples like CH₃COONa, NH₄Cl, NaCl, and NH₄OOCCH₃).

3. **Analyze Each Salt**:
- **CH₃COONa (Sodium Acetate)**:
- This salt is derived from a weak acid (acetic acid) and a strong base (sodium hydroxide).
- It hydrolyzes to produce a basic solution, resulting in a higher pH.

- **NH₄Cl (Ammonium Chloride)**:
- This salt is derived from a strong acid (HCl) and a weak base (NH₄OH).
- It hydrolyzes to produce NH₄⁺ ions, which can release H⁺ ions, leading to a lower pH compared to CH₃COONa.

- **NaCl (Sodium Chloride)**:
- This salt is derived from a strong acid (HCl) and a strong base (NaOH).
- It does not affect the pH significantly, resulting in a neutral pH (around 7).

- **NH₄OOCCH₃ (Ammonium Acetate)**:
- This salt is derived from a weak acid (acetic acid) and a weak base (NH₄OH).
- It will not significantly change the pH, similar to CH₃COONa.

4. **Compare the pH Values**:
- From the analysis:
- CH₃COONa: Higher pH (basic).
- NH₄Cl: Lower pH (acidic).
- NaCl: Neutral pH (7).
- NH₄OOCCH₃: Similar to CH₃COONa (not significantly acidic).

5. **Conclusion**:
- Among the salts analyzed, **NH₄Cl** will have the lowest pH value due to its ability to release H⁺ ions in solution, making it the most acidic.

### Final Answer:
The aqueous solution of salts that has the lowest pH value is **NH₄Cl**.