What is the standard potential $E^{\circ}$ of the cell Zn | Zn2+ (1M) || I- (1M) | CuI | Cu, if the $E_{Zn^{2+}|Zn}^{\circ}=-0.76$ V and $E_{Cu^{+}|Cu}^{\circ}=-0.17V$:

Question

Accepted Answer

To determine the standard potential $ E^{\circ} $ of the cell Zn | Zn$^{2+}$ (1M) || I$^{-}$ (1M) | CuI | Cu, we need to consider the standard reduction potentials given for the half-reactions involved in the cell.

### Explanation for Option 4 (Correct Answer: 0.59 V)

1. **Cell Reaction**: 
   - The cell consists of two half-cells: 
     - Anode: Zn | Zn$^{2+}$ (oxidation)
     - Cathode: CuI | Cu (reduction)

2. **Standard Reduction Potentials**:
   - $ E_{Zn^{2+}|Zn}^{\circ} = -0.76 \, \text{V} $
   - $ E_{Cu^{+}|Cu}^{\circ} = -0.17 \, \text{V} $

3. **Cell Potential Calculation**:
   - The overall cell reaction involves the oxidation of Zn to Zn$^{2+}$ and the reduction of CuI to Cu.
   - The standard cell potential $ E_{\text{cell}}^{\circ} $ is calculated using the formula:
     $$
     E_{\text{cell}}^{\circ} = E_{\text{cathode}}^{\circ} - E_{\text{anode}}^{\circ}
     $$
   - Substituting the given values:
     $$
     E_{\text{cell}}^{\circ} = (-0.17 \, \text{V}) - (-0.76 \, \text{V}) = 0.59 \, \text{V}
     $$

4. **Conclusion**:
   - The calculated standard cell potential is 0.59 V, which matches Option 4. Therefore, Option 4 is the correct answer.

### Explanation for Why Other Options are Incorrect:

1. **Option 1 (1.1 V)**:
   - This value is incorrect because it does not match the calculated standard cell potential of 0.59 V. The calculation clearly shows that the potential difference between the cathode and anode is 0.59 V, not 1.1 V.

2. **Option 2 (0.93 V)**:
   - This value is incorrect because it exceeds the calculated standard cell potential. The difference between the cathode and anode potentials is 0.59 V, as derived from the given standard reduction potentials.

3. **Option 3 (-0.93 V)**:
   - This value is incorrect because it suggests a negative cell potential, which is not possible given the positive potential difference calculated. The standard cell potential is positive, indicating a spontaneous reaction under standard conditions.

By following the standard procedure for calculating cell potentials and using the given standard reduction potentials, we confirm that Option 4 (0.59 V) is indeed the correct answer.