Sodium cannot be obtained by the electrolysis of aqueous solution of `NaCl` using `Pt` electrodes.

Explanation

To understand why sodium cannot be obtained by the electrolysis of an aqueous solution of NaCl using platinum (Pt) electrodes, we can break down the process step by step.

### Step-by-Step Solution:

1. **Understanding Electrolysis of Aqueous NaCl**:
- When NaCl is dissolved in water, it dissociates into sodium ions (Na⁺) and chloride ions (Cl⁻). The solution also contains water (H₂O).

2. **Identifying Possible Reactions**:
- During electrolysis, two main reactions can occur:
- Reduction (gain of electrons) at the cathode.
- Oxidation (loss of electrons) at the anode.

3. **Reduction Reactions**:
- At the cathode, we can have two possible reduction reactions:
- Reduction of sodium ions:
\[ \text{Na}^+ + e^- \rightarrow \text{Na (s)} \quad \text{(Standard Reduction Potential: } E^\circ = -2.71 \text{ V)} \]
- Reduction of water:
\[ 2\text{H}_2\text{O} + 2e^- \rightarrow \text{H}_2(g) + 2\text{OH}^- \quad \text{(Standard Reduction Potential: } E^\circ = -0.828 \text{ V)} \]

4. **Comparing Standard Reduction Potentials**:
- The standard reduction potential (E°) indicates the tendency of a species to gain electrons. The more positive the value, the more favorable the reaction.
- Here, the standard reduction potential of water (-0.828 V) is higher (less negative) than that of sodium (-2.71 V). This means that water is more likely to be reduced than sodium ions.

5. **Conclusion on Feasibility**:
- Since the reduction of water is more favorable than the reduction of sodium ions, during electrolysis, water will be reduced to hydrogen gas instead of sodium being deposited.
- Therefore, sodium cannot be obtained from the electrolysis of an aqueous solution of NaCl using Pt electrodes.

6. **Final Reaction at the Cathode**:
- The actual reaction occurring at the cathode will be:
\[ 2\text{H}_2\text{O} + 2e^- \rightarrow \text{H}_2(g) + 2\text{OH}^- \]

### Summary:
Sodium cannot be obtained from the electrolysis of an aqueous NaCl solution using Pt electrodes because the reduction of water is more thermodynamically favorable than the reduction of sodium ions, leading to the production of hydrogen gas instead.