By which copper is purified ?

Options

A. By heating
B. By oxidation
C. By electric-decomposition
D. By circular processing

Explanation

To purify copper, the method used is called electrolysis or electro-decomposition. Here’s a step-by-step solution to understand the process:

### Step-by-Step Solution:

1. **Understanding the Process**:
- Copper can be purified using the method of electrolysis, which involves the use of electric current to drive a chemical reaction.

2. **Setting Up the Apparatus**:
- A vessel is prepared where two electrodes are placed. One electrode is made of impure copper (this will act as the anode) and the other is made of pure copper (this will act as the cathode).

3. **Choosing the Electrolyte**:
- An electrolyte solution is prepared, typically using copper(II) sulfate (CuSO₄). This solution will facilitate the movement of copper ions.

4. **Connecting the Power Supply**:
- The electrodes are connected to a power supply. The impure copper electrode (anode) is connected to the positive terminal, while the pure copper electrode (cathode) is connected to the negative terminal.

5. **Electrolysis Reaction**:
- When the electric current is passed through the solution, copper ions from the anode dissolve into the solution, while copper ions from the solution are deposited onto the cathode. This process continues until the impure copper is dissolved and pure copper is deposited.

6. **Completion of the Process**:
- After a certain period, the process is stopped, and the pure copper is collected from the cathode. The impurities remain at the anode or fall to the bottom of the vessel.

### Final Answer:
Copper is purified by the process of electrolysis (or electro-decomposition).

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