Which one of the following electrolytes would dissolve in water to give a 0.1M solution with pH about 9

Options

A. `CH_(3)COOH`
B. `CH_(3)COONa`
C. `NH_(4)Cl`
D. KOH

Explanation

To determine which electrolyte would dissolve in water to give a 0.1 M solution with a pH of about 9, we can analyze the properties of the given electrolytes.

### Step-by-Step Solution:

1. **Understanding pH and its Relation to Acidity and Basicity**:
- The pH scale ranges from 0 to 14. A pH of 7 is neutral, below 7 is acidic, and above 7 is basic.
- A pH of about 9 indicates a weakly basic solution.

2. **Analyzing the Given Electrolytes**:
- **Acetic Acid (CH₃COOH)**: This is a weak acid. A solution of acetic acid will have a pH less than 7.
- **Sodium Acetate (CH₃COONa)**: This is the salt of a weak acid (acetic acid) and a strong base (sodium hydroxide). It will hydrolyze in water to produce a basic solution, leading to a pH greater than 7.
- **Ammonium Chloride (NH₄Cl)**: This is a salt of a weak base (ammonia) and a strong acid (hydrochloric acid). It will produce an acidic solution, resulting in a pH less than 7.
- **Potassium Hydroxide (KOH)**: This is a strong base. A 0.1 M solution of KOH will have a pH well above 12.
- **Sodium Chloride (NaCl)**: This is a neutral salt, and a solution of NaCl will have a pH of about 7.

3. **Determining the Suitable Electrolyte**:
- From the analysis, the only electrolyte that can produce a solution with a pH around 9 is **Sodium Acetate (CH₃COONa)**. This is because it will hydrolyze to produce hydroxide ions (OH⁻), making the solution basic.

4. **Conclusion**:
- Therefore, the electrolyte that would dissolve in water to give a 0.1 M solution with a pH of about 9 is **Sodium Acetate (CH₃COONa)**.

### Final Answer:
**Sodium Acetate (CH₃COONa)**