In which of the following processes colloidal sulphur is formed

Options

A. `FeCl_2+H_2S`
B. `FeCl_3+H_2S`
C. Fe+ H_2SO_4
D. `SO_2+Cl_2`

Answer

To determine in which of the given processes colloidal sulfur is formed, we will analyze each reaction step by step.

### Step 1: Analyze the first reaction
**Reaction:** FeCl2 + H2S → FeS + 2HCl

- In this reaction, iron(II) chloride reacts with hydrogen sulfide to form iron(II) sulfide and hydrochloric acid.
- **Observation:** There is no formation of sulfur in this reaction.

**Conclusion:** The first option does not produce colloidal sulfur.

**Hint:** Check if sulfur is a product in the reaction.

### Step 2: Analyze the second reaction
**Reaction:** FeCl3 + H2S → 2FeCl2 + S + 2HCl

- Here, iron(III) chloride reacts with hydrogen sulfide to produce iron(II) chloride, sulfur, and hydrochloric acid.
- **Observation:** Sulfur is produced in this reaction.

**Conclusion:** The second option produces colloidal sulfur.

**Hint:** Look for the presence of sulfur as a product.

### Step 3: Analyze the third reaction
**Reaction:** Fe + H2SO4 → Fe2(SO4)3 + 3SO2 + 6H2O

- In this reaction, iron reacts with sulfuric acid to form iron(III) sulfate, sulfur dioxide, and water.
- **Observation:** There is no formation of sulfur in this reaction.

**Conclusion:** The third option does not produce colloidal sulfur.

**Hint:** Ensure that sulfur is not just in a different oxidation state but is actually formed as a product.

### Step 4: Analyze the fourth reaction
**Reaction:** SO2 + Cl2 → (No reaction leading to sulfur formation)

- This reaction involves sulfur dioxide and chlorine, but it does not yield colloidal sulfur.
- **Observation:** There is no formation of colloidal sulfur in this reaction.

**Conclusion:** The fourth option does not produce colloidal sulfur.

**Hint:** Verify if the reaction leads to the formation of elemental sulfur.

### Final Conclusion:
After analyzing all the reactions, we find that colloidal sulfur is formed only in the second reaction (FeCl3 + H2S). Therefore, the correct answer is:

**Correct Option:** The second option.