For the galvanic cell, `Cu|Cu^(2+)"||"Ag^(+)|Ag`. Which of the following observations is not correct ?

Options

A. Cu acts as anode and Ag acts as cathode.
B. Ag electrode loses mass and Cu electrode gains mass.
C. Reaction at anode, `Cu to Cu^(2+) + 2e^-`
D. Copper is more reactive than silver .

Explanation

To solve the question regarding the galvanic cell represented as `Cu|Cu^(2+)"||"Ag^(+)|Ag`, we need to analyze the cell and its components step by step.

### Step-by-Step Solution:

1. **Identify the Components of the Galvanic Cell**:
- The cell notation `Cu|Cu^(2+)"||"Ag^(+)|Ag` indicates that copper (Cu) is on the left side and silver (Ag) is on the right side.
- The left side represents the anode and the right side represents the cathode.

2. **Determine the Reactions at Anode and Cathode**:
- At the anode (left side, Cu), oxidation occurs:
\[ \text{Cu} \rightarrow \text{Cu}^{2+} + 2e^- \]
- At the cathode (right side, Ag), reduction occurs:
\[ \text{Ag}^+ + e^- \rightarrow \text{Ag} \]

3. **Analyze Mass Changes**:
- Since oxidation occurs at the anode, the mass of the copper electrode will decrease as copper is converted to Cu²⁺ ions.
- Conversely, at the cathode, the silver ions (Ag⁺) gain electrons and are deposited as solid silver, so the mass of the silver electrode will increase.

4. **Evaluate the Given Statements**:
- **Statement A**: "Copper acts as anode and Ag acts as cathode."
- This is correct because Cu is oxidized (loses electrons) and Ag is reduced (gains electrons).
- **Statement B**: "Ag electrode loses mass and copper electrode gains mass."
- This is incorrect because the copper electrode loses mass while the silver electrode gains mass.
- **Statement C**: "Reaction at anode is Cu gives Cu²⁺ + 2 electrons."
- This is correct as per the oxidation reaction at the anode.
- **Statement D**: "Copper is more reactive than silver."
- This is also correct according to the reactivity series.

5. **Conclusion**:
- The observation that is not correct is **Statement B**: "Ag electrode loses mass and copper electrode gains mass."

### Final Answer:
The observation that is not correct is: **Ag electrode loses mass and copper electrode gains mass.**