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 will analyze the interaction between acetic acid (CH₃COOH) and sodium hydroxide (NaOH) and understand the concept of the reverse ion effect.

### Step-by-Step Solution:

1. **Understanding the Components**:
- Acetic acid (CH₃COOH) is a weak acid that partially dissociates in solution to form CH₃COO⁻ (acetate ion) and H⁺ (hydrogen ion).
- Sodium hydroxide (NaOH) is a strong base that completely dissociates in solution to form Na⁺ and OH⁻ ions.

2. **Reaction Between Acetic Acid and Sodium Hydroxide**:
- When NaOH is added to a solution of acetic acid, the OH⁻ ions from NaOH will react with the H⁺ ions from acetic acid to form water (H₂O).
- The reaction can be represented as:
\[ \text{CH}_3\text{COOH} + \text{OH}^- \rightarrow \text{CH}_3\text{COO}^- + \text{H}_2\text{O} \]

3. **Effect of Adding NaOH**:
- The reaction consumes H⁺ ions, which decreases the concentration of H⁺ in the solution.
- According to Le Chatelier's principle, if the concentration of H⁺ ions decreases, the equilibrium of the dissociation of acetic acid will shift to the right to produce more H⁺ ions.

4. **Increased Ionization of Acetic Acid**:
- As the equilibrium shifts to the right, more acetic acid dissociates into CH₃COO⁻ and H⁺, leading to an increase in the ionization of acetic acid.

5. **Naming the Effect**:
- This phenomenon, where the addition of a strong base leads to increased dissociation of a weak acid due to the removal of H⁺ ions, is known as the **reverse ion effect**.

6. **Conclusion**:
- Therefore, when a strong base like NaOH is added to a weak acid like acetic acid, the dissociation of acetic acid increases due to the neutralization of H⁺ ions, and this effect is termed the **reverse ion effect**.

### Final Answer:
The effect is known as the **reverse ion effect**.