When a copper rod is dipped in aqueous silver nitrate solution , the colour of the solution changes to blue . This is because

Options

A. Cu is more easily reduced than Ag
B. Ag is more easily reduced than Cu
C. Nitrate ion acts as an oxidizing agent
D. Nitrate ion acts as a reducing agent

Explanation

To understand why the color of the silver nitrate solution changes to blue when a copper rod is dipped into it, we can break down the process step by step:

### Step 1: Understanding the Reactants
- **Copper Rod (Cu)**: Copper is a more reactive metal compared to silver.
- **Silver Nitrate (AgNO₃)**: This is an aqueous solution containing silver ions (Ag⁺) and nitrate ions (NO₃⁻).

### Step 2: Initial Condition
- When the copper rod is placed in the silver nitrate solution, the solution is initially colorless because of the presence of silver ions.

### Step 3: Displacement Reaction
- Due to the higher reactivity of copper compared to silver, a displacement reaction occurs. Copper displaces silver from the silver nitrate solution.
- The reaction can be represented as:
\[ \text{Cu (s)} + 2 \text{AgNO}_3 (aq) \rightarrow \text{Cu(NO}_3)_2 (aq) + 2 \text{Ag (s)} \]

### Step 4: Formation of Copper(II) Nitrate
- As copper displaces silver, it forms copper(II) nitrate (Cu(NO₃)₂), which is blue in color. This is why the solution changes color.

### Step 5: Observing the Color Change
- The blue color of the solution is due to the formation of copper(II) ions (Cu²⁺) in the solution, which imparts a blue hue.

### Conclusion
- The color change to blue indicates that copper has reacted with silver nitrate, displacing silver and forming copper(II) nitrate in the solution.

### Summary of the Reaction
- The overall reaction is a single displacement reaction where copper displaces silver from silver nitrate, resulting in a color change due to the formation of copper(II) ions.

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