Acetic acid dissociates as
`CH_(3) "COOH" hArr CH_(3) "COO"^(-) + H^(+)` . If a little amount of sodium acetate is added to its aqueous solution

Options

A. The acid dissociates further
B. The `H^(+)` ion concentration increases
C. The acid dissocitation is suppressed
D. The equilibrium is unaffected

Answer

To solve the problem regarding the dissociation of acetic acid when sodium acetate is added, we can follow these steps:

### Step-by-Step Solution:

1. **Write the Dissociation Reaction of Acetic Acid:**
The dissociation of acetic acid (CH₃COOH) can be represented as:
\[ \text{CH}_3\text{COOH} \rightleftharpoons \text{CH}_3\text{COO}^- + \text{H}^+ \]

2. **Understand the Effect of Adding Sodium Acetate:**
When sodium acetate (CH₃COONa) is added to the solution, it dissociates completely into sodium ions (Na⁺) and acetate ions (CH₃COO⁻):
\[ \text{CH}_3\text{COONa} \rightarrow \text{CH}_3\text{COO}^- + \text{Na}^+ \]
This increases the concentration of acetate ions (CH₃COO⁻) in the solution.

3. **Apply Le Chatelier's Principle:**
According to Le Chatelier's Principle, if a system at equilibrium is disturbed by changing the concentration of one of the reactants or products, the system will shift in a direction that counteracts the disturbance. In this case, the addition of acetate ions increases their concentration.

4. **Determine the Shift in Equilibrium:**
Since the concentration of acetate ions (CH₃COO⁻) has increased, the equilibrium will shift to the left to reduce the concentration of acetate ions. This means that the dissociation of acetic acid will be suppressed:
\[ \text{CH}_3\text{COOH} \rightleftharpoons \text{CH}_3\text{COO}^- + \text{H}^+ \quad \text{(shift left)} \]

5. **Conclude the Effect on Hydrogen Ion Concentration:**
As a result of the shift to the left, the concentration of hydrogen ions (H⁺) will decrease. Therefore, the dissociation of acetic acid is suppressed.

6. **Evaluate the Options:**
Based on the analysis:
- The dissociation of acetic acid is suppressed.
- The concentration of H⁺ ions decreases.
- The equilibrium is affected.

Thus, the correct conclusion is that the dissociation of the acid is suppressed.

### Final Answer:
The dissociation of acetic acid is suppressed due to the common ion effect from the added sodium acetate.

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