A solutions containing NaOH and NaCl shows common ion effect.

Answer

To determine whether a solution containing NaOH (sodium hydroxide) and NaCl (sodium chloride) shows the common ion effect, we can analyze the components and their behavior in solution.

### Step-by-Step Solution:

1. **Understanding the Common Ion Effect**:
- The common ion effect refers to the decrease in the solubility of a weak electrolyte when a strong electrolyte that shares a common ion is added to the solution. This is due to Le Chatelier's principle, which states that the equilibrium will shift to counteract the change.

2. **Identifying the Electrolytes**:
- In this case, NaOH and NaCl are both strong electrolytes. Strong electrolytes completely dissociate in solution.
- NaOH dissociates into Na⁺ and OH⁻ ions:
\[ \text{NaOH} \rightarrow \text{Na}^+ + \text{OH}^- \]
- NaCl dissociates into Na⁺ and Cl⁻ ions:
\[ \text{NaCl} \rightarrow \text{Na}^+ + \text{Cl}^- \]

3. **Common Ion Analysis**:
- Both NaOH and NaCl produce Na⁺ ions when dissolved in water. Therefore, the Na⁺ ion is a common ion in this scenario.
- However, since both NaOH and NaCl are strong electrolytes, they do not establish an equilibrium with a weak electrolyte.

4. **Conclusion**:
- Since both NaOH and NaCl are strong electrolytes, they do not exhibit the common ion effect. The presence of the common ion (Na⁺) does not suppress the dissociation of any weak electrolyte because there is no weak electrolyte present in this solution.
- Therefore, the statement that a solution containing NaOH and NaCl shows the common ion effect is **false**.

### Final Answer:
A solution containing NaOH and NaCl does not show the common ion effect. This statement is false.