On the electrolysis of an aqueous solution of NaF using the gram equivalence of an electrolyte

Options

A. Na is obtained at cathode
B. `F_2` is obtainėd at anode
C. `H_2` is obtained at cathode
D. `O_2` is oblained at anode

Answer

To solve the question regarding the electrolysis of an aqueous solution of NaF, we will analyze the reactions occurring at both the cathode and anode during the process.

### Step-by-Step Solution:

1. **Identify the Electrolyte**: The electrolyte in this case is an aqueous solution of sodium fluoride (NaF). In solution, NaF dissociates into sodium ions (Na⁺) and fluoride ions (F⁻).

2. **Determine the Reactions at the Cathode**:
- During electrolysis, at the cathode (the negative electrode), reduction occurs.
- In an aqueous solution, the possible reduction reactions are:
- Reduction of H⁺ ions to form hydrogen gas (H₂).
- Reduction of Na⁺ ions to form sodium metal (Na).
- However, since sodium is a very reactive metal, it does not get deposited in an aqueous solution. Instead, H⁺ ions from water are reduced.
- The half-reaction at the cathode can be written as:
\[ 2H^+ + 2e^- \rightarrow H_2(g) \]
- Thus, hydrogen gas (H₂) is produced at the cathode.

3. **Determine the Reactions at the Anode**:
- At the anode (the positive electrode), oxidation occurs.
- The possible oxidation reactions include:
- Oxidation of OH⁻ ions to form oxygen gas (O₂).
- Oxidation of F⁻ ions to form fluorine gas (F₂).
- In an aqueous solution, the oxidation of OH⁻ ions is more favorable than the oxidation of F⁻ ions.
- The half-reaction at the anode can be written as:
\[ 4OH^- \rightarrow 2H_2O + O_2(g) + 4e^- \]
- Therefore, oxygen gas (O₂) is produced at the anode.

4. **Summary of Products**:
- At the cathode: Hydrogen gas (H₂) is produced.
- At the anode: Oxygen gas (O₂) is produced.
- The sodium ions (Na⁺) and fluoride ions (F⁻) remain in the solution and do not get discharged.

5. **Evaluate the Statements**:
- Statement 1: Na is obtained at the cathode. **(False)**
- Statement 2: F₂ is obtained at the anode. **(False)**
- Statement 3: H₂ is obtained at the cathode. **(True)**
- Statement 4: O₂ is obtained at the anode. **(True)**

### Final Conclusion:
The correct statements regarding the electrolysis of an aqueous solution of NaF are that hydrogen gas (H₂) is produced at the cathode, and oxygen gas (O₂) is produced at the anode.