`E^@` for `Mg to 2e^(-) + Mg^(2+) ` is `+ 2.37 V` and for `Cu to 2e^(-) + Cu^(+2)` is `-0.34V` . What will be the standard potential of cell constructed with these electrodes ? Which electrode will be positive terminal to draw the current?

Answer

To solve the problem, we need to determine the standard cell potential for the electrochemical cell constructed with magnesium and copper electrodes. We will also identify which electrode acts as the positive terminal.

### Step-by-Step Solution:

1. **Identify the Standard Reduction Potentials**:
- Given:
- For magnesium: \( E^\circ_{\text{Mg}^{2+}/\text{Mg}} = +2.37 \, \text{V} \) (this is the oxidation potential)
- For copper: \( E^\circ_{\text{Cu}^{2+}/\text{Cu}} = -0.34 \, \text{V} \) (this is also the oxidation potential)

2. **Convert Oxidation Potentials to Reduction Potentials**:
- The reduction potential for magnesium can be calculated by changing the sign of the oxidation potential:
\[ E^\circ_{\text{Mg}^{2+}/\text{Mg}} = -2.37 \, \text{V} \]
- The reduction potential for copper remains as is:
\[ E^\circ_{\text{Cu}^{2+}/\text{Cu}} = +0.34 \, \text{V} \]

3. **Determine the Anode and Cathode**:
- The anode is where oxidation occurs, and the cathode is where reduction occurs.
- Since the reduction potential of copper (+0.34 V) is greater than that of magnesium (-2.37 V), copper will act as the cathode and magnesium will act as the anode.

4. **Calculate the Standard Cell Potential**:
- The standard cell potential \( E^\circ_{\text{cell}} \) can be calculated using the formula:
\[ E^\circ_{\text{cell}} = E^\circ_{\text{cathode}} - E^\circ_{\text{anode}} \]
- Substituting the values:
\[ E^\circ_{\text{cell}} = E^\circ_{\text{Cu}} - E^\circ_{\text{Mg}} = (+0.34 \, \text{V}) - (-2.37 \, \text{V}) \]
- This simplifies to:
\[ E^\circ_{\text{cell}} = 0.34 + 2.37 = 2.71 \, \text{V} \]

5. **Identify the Positive Terminal**:
- The positive terminal of the cell is the cathode, which is the copper electrode in this case.

### Final Answers:
- The standard potential of the cell is \( 2.71 \, \text{V} \).
- The positive terminal to draw the current is the copper electrode.