Which of the following will supress the ionisation of acetic acid in aquoeus solution ?

Options

A. `NaCI`
B. `HCI`
C. `KCI`
D. Unpredictable

Explanation

To determine which of the following will suppress the ionization of acetic acid in an aqueous solution, we need to understand the concept of the common ion effect.

### Step-by-Step Solution:

1. **Identify the Nature of Acetic Acid**:
- Acetic acid (CH₃COOH) is a weak electrolyte. This means it does not completely ionize in solution. In water, it partially dissociates into acetate ions (CH₃COO⁻) and hydrogen ions (H⁺).
- The ionization can be represented as:
\[ \text{CH}_3\text{COOH} \rightleftharpoons \text{CH}_3\text{COO}^- + \text{H}^+ \]

2. **Understand the Common Ion Effect**:
- The common ion effect states that the addition of a strong electrolyte that shares a common ion with a weak electrolyte will suppress the ionization of the weak electrolyte.
- In this case, if we add a strong acid (which provides H⁺ ions), it will shift the equilibrium of the acetic acid dissociation to the left, reducing the ionization of acetic acid.

3. **Analyze the Options**:
- If the options include strong acids (like HCl), they will provide H⁺ ions, which are common with the ions produced by acetic acid.
- Therefore, the presence of H⁺ from a strong acid will suppress the ionization of acetic acid.

4. **Conclusion**:
- Among the options provided, the one that will suppress the ionization of acetic acid is a strong acid that provides H⁺ ions, such as HCl.

### Final Answer:
- The correct option is **HCl**.

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