From a solution of `CuSO_4` the metal used to recover copper is

Options

A. `Na`
B. `Ag`
C. `Hg`
D. `Fe`

Explanation

To solve the question of which metal can be used to recover copper from a solution of CuSO₄, we can follow these steps:

### Step 1: Understand the Reaction
We need to recognize that the process of recovering copper from copper sulfate (CuSO₄) involves a displacement reaction. In such reactions, a more reactive metal displaces a less reactive metal from its compound.

### Step 2: Identify the Metals
The metals given in the options are:
1. Na (Sodium)
2. Ag (Silver)
3. Hg (Mercury)
4. Fe (Iron)

### Step 3: Determine Reactivity
We need to compare the reactivity of these metals with copper. The reactivity series of metals helps us understand which metals can displace others from their compounds. The order of reactivity from most reactive to least reactive is:
- Sodium (Na)
- Iron (Fe)
- Mercury (Hg)
- Silver (Ag)
- Copper (Cu)

### Step 4: Analyze Each Option
- **Na (Sodium)**: Highly reactive but not typically used in this context due to its vigorous reactions with water.
- **Ag (Silver)**: Less reactive than copper; cannot displace copper from CuSO₄.
- **Hg (Mercury)**: Also less reactive than copper; cannot displace copper from CuSO₄.
- **Fe (Iron)**: More reactive than copper; can displace copper from CuSO₄.

### Step 5: Write the Reaction
The reaction for the displacement of copper by iron can be written as:
\[ \text{Fe} + \text{CuSO}_4 \rightarrow \text{Cu} + \text{FeSO}_4 \]

### Step 6: Conclusion
Since iron (Fe) is the only metal among the options that can displace copper from copper sulfate, the correct answer is **Fe**.

### Final Answer
The metal used to recover copper from a solution of CuSO₄ is **Fe (Iron)**.

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