When strong base (NaOH) is added to the weak (acid , `CH_3COOH`) , then dissociation of acetic acid increase, this effect is known as

Options

A. common ion effect
B. reverse ion effect
C. saltation effect
D. solubility effect

Answer

To solve the question, we need to understand the interaction between a strong base (NaOH) and a weak acid (acetic acid, CH₃COOH) and how it affects the dissociation of the weak acid.

### Step-by-step Solution:

1. **Understanding the Dissociation of Acetic Acid**:
- Acetic acid (CH₃COOH) is a weak acid that partially dissociates in water to form acetate ions (CH₃COO⁻) and hydrogen ions (H⁺).
- The dissociation can be represented as:
\[ \text{CH}_3\text{COOH} \rightleftharpoons \text{CH}_3\text{COO}^- + \text{H}^+ \]

2. **Adding a Strong Base (NaOH)**:
- When NaOH is added to the solution, it dissociates completely into sodium ions (Na⁺) and hydroxide ions (OH⁻):
\[ \text{NaOH} \rightarrow \text{Na}^+ + \text{OH}^- \]

3. **Reaction Between H⁺ and OH⁻**:
- The hydroxide ions (OH⁻) from NaOH will react with the hydrogen ions (H⁺) produced from the dissociation of acetic acid to form water:
\[ \text{H}^+ + \text{OH}^- \rightarrow \text{H}_2\text{O} \]

4. **Effect on Equilibrium**:
- According to Le Chatelier's principle, if the concentration of a product decreases (in this case, H⁺ ions), the equilibrium will shift to the right to counteract this change. This means that more acetic acid will dissociate to produce more H⁺ and CH₃COO⁻ ions.
- Thus, the dissociation of acetic acid increases.

5. **Identifying the Effect**:
- The phenomenon where the addition of a strong base increases the dissociation of a weak acid is known as the **"reverse ion effect."**

### Conclusion:
The correct answer to the question is that the effect observed when a strong base (NaOH) is added to a weak acid (acetic acid) is known as the **reverse ion effect**.

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