Which metal can deposit copper from copper sulphate solution ?

Options

A. Mercury
B. Iron
C. Gold
D. Platinum

Explanation

To determine which metal can deposit copper from a copper sulfate solution, we need to analyze the standard reduction potentials of the metals involved. Here’s a step-by-step solution:

### Step 1: Understand the Reaction
Copper (Cu) in copper sulfate (CuSO₄) exists in the +2 oxidation state (Cu²⁺). To deposit copper from this solution, we need a metal that can reduce Cu²⁺ to Cu (0).

### Step 2: Identify the Metals
The options given are:
- A) Mercury (Hg)
- B) Iron (Fe)
- C) Gold (Au)
- D) Platinum (Pt)

### Step 3: Look Up Standard Reduction Potentials
We need to compare the standard reduction potentials (E°) of copper and the other metals. The standard reduction potential for copper (Cu²⁺ + 2e⁻ → Cu) is +0.34 V.

- E° (Cu²⁺/Cu) = +0.34 V
- E° (Hg²⁺/Hg) = +0.85 V
- E° (Fe²⁺/Fe) = -0.44 V
- E° (Au³⁺/Au) = +1.50 V
- E° (Pt²⁺/Pt) = +1.20 V

### Step 4: Compare the Potentials
For a metal to displace copper from copper sulfate, its E° must be less than that of copper. This means:
- If E° (metal) < E° (Cu), the metal can reduce Cu²⁺ to Cu.

Now, we analyze each option:
- **Mercury (Hg)**: E° (Hg) = +0.85 V > +0.34 V (cannot displace)
- **Iron (Fe)**: E° (Fe) = -0.44 V < +0.34 V (can displace)
- **Gold (Au)**: E° (Au) = +1.50 V > +0.34 V (cannot displace)
- **Platinum (Pt)**: E° (Pt) = +1.20 V > +0.34 V (cannot displace)

### Step 5: Conclusion
The only metal that can deposit copper from copper sulfate solution is **Iron (Fe)**.

### Final Answer
**Option B: Iron (Fe)** can deposit copper from copper sulfate solution.

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