Copper cannot replace__________from solution

Options

A. Fe
B. Au
C. Hg
D. Ag

Explanation

To solve the question "Copper cannot replace__________from solution," we will analyze the electrochemical series and the reduction potentials of various metals.

### Step-by-Step Solution:

1. **Understanding the Concept**:
- In electrochemistry, a metal can only displace another metal from its salt solution if it has a higher reduction potential. The metal with a higher reduction potential will be reduced (gain electrons) while the other metal will be oxidized (lose electrons).

2. **Identify the Metals in the Question**:
- The metals mentioned in the video transcript are:
- F (Fluorine)
- Au (Gold)
- H (Hydrogen)
- G (not specified, but likely refers to a metal like Gallium)
- Ag (Silver)
- Hg (Mercury)

3. **List the Reduction Potentials**:
- According to the transcript, the reduction potentials are as follows:
- Au³⁺ + 3e⁻ → Au: +1.68 V
- Hg²⁺ + 2e⁻ → Hg: +0.85 V
- Ag⁺ + e⁻ → Ag: +0.80 V
- Cu²⁺ + 2e⁻ → Cu: +0.34 V
- H⁺ + e⁻ → H₂: 0.00 V
- Fe²⁺ + 2e⁻ → Fe: -0.41 V

4. **Comparison of Reduction Potentials**:
- Now, we compare the reduction potential of copper (Cu²⁺) with the other metals:
- Cu: +0.34 V
- Au: +1.68 V (higher than Cu)
- Hg: +0.85 V (higher than Cu)
- Ag: +0.80 V (higher than Cu)
- H: 0.00 V (higher than Cu)
- Fe: -0.41 V (lower than Cu)

5. **Conclusion**:
- Since copper has a lower reduction potential than gold (Au), mercury (Hg), silver (Ag), and hydrogen (H), it cannot replace these metals from their solutions. However, copper can replace iron (Fe) since it has a higher reduction potential than iron.

6. **Final Answer**:
- Therefore, the answer to the question "Copper cannot replace__________from solution" is **Au (Gold)**, **Hg (Mercury)**, **Ag (Silver)**, or **H (Hydrogen)**.