Name the common elements present in the anode mud in electrolytic refining of copper. Why are they so present?

Options

A. Selenium
B. Tellurium
C. Silver
D. Gold

Explanation

### Step-by-Step Solution:

1. **Understanding Electrolytic Refining of Copper**:
- In the electrolytic refining process, two electrodes are used: an anode (impure copper) and a cathode (pure copper). The electrolyte is a solution of copper sulfate (CuSO₄).

2. **Process Overview**:
- When electric current is passed through the solution, the impure copper at the anode dissolves into the solution as Cu²⁺ ions.
- These ions then migrate towards the cathode, where they are reduced and deposit as pure copper.

3. **Formation of Anode Mud**:
- As the impure copper dissolves, impurities that do not dissolve remain at the bottom of the electrolytic cell, forming what is known as anode mud.

4. **Common Elements in Anode Mud**:
- The common elements found in the anode mud include:
- Selenium (Se)
- Tellurium (Te)
- Silver (Ag)
- Gold (Au)
- Platinum (Pt)

5. **Reason for Their Presence**:
- These elements are present in the anode mud because they are less reactive than copper and do not dissolve in the copper sulfate solution.
- They remain as solid residues due to their inability to form soluble ions in the electrolyte.

### Final Answer:
The common elements present in the anode mud in the electrolytic refining of copper are selenium, tellurium, silver, gold, and platinum. They are present because they are less reactive than copper and do not dissolve in the copper sulfate solution.