During the electrolysis of a concentrated brine solution, Calculated the moles of chlorine gas produced by the passage of 4F electricity.

Answer

To calculate the moles of chlorine gas produced during the electrolysis of a concentrated brine solution by the passage of 4 Faraday of electricity, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Electrolysis Process**:
- During the electrolysis of brine (aqueous NaCl), chlorine gas (Cl₂) is produced at the anode.

2. **Identify the Reaction**:
- The half-reaction at the anode can be represented as:
\[ 2Cl^- \rightarrow Cl_2 + 2e^- \]
- This indicates that 2 moles of electrons are needed to produce 1 mole of chlorine gas.

3. **Use Faraday's Law**:
- According to Faraday's first law of electrolysis, the amount of substance produced at an electrode is directly proportional to the amount of electric charge passed through the electrolyte.
- The relationship can be expressed as:
\[ \text{Charge (Q)} = n \cdot F \]
- Where \( n \) is the number of moles of electrons and \( F \) is Faraday's constant (approximately 96500 C/mol).

4. **Calculate Moles of Electrons**:
- Given that 4 Faraday of electricity is passed, we can calculate the total charge:
\[ Q = 4 \, \text{Faraday} \times 96500 \, \text{C/Faraday} = 386000 \, \text{C} \]
- The number of moles of electrons (n) can be calculated as:
\[ n = \frac{Q}{F} = \frac{386000 \, \text{C}}{96500 \, \text{C/mol}} = 4 \, \text{moles of electrons} \]

5. **Relate Moles of Chlorine to Moles of Electrons**:
- From the half-reaction, we know that 2 moles of electrons produce 1 mole of chlorine gas:
\[ \text{Moles of Cl}_2 = \frac{\text{Moles of electrons}}{2} \]
- Therefore:
\[ \text{Moles of Cl}_2 = \frac{4 \, \text{moles of electrons}}{2} = 2 \, \text{moles of Cl}_2 \]

### Final Answer:
The moles of chlorine gas produced by the passage of 4 Faraday of electricity is **2 moles**.