Which of the following halogens can oxidise `H_(2)S` to S?

Options

A. `Cl_(2)`
B. `F_(2)`
C. `Br_(2)`
D. All of these

Answer

To determine which halogens can oxidize H₂S to sulfur (S), we need to analyze the oxidation states of sulfur in the reactants and products when reacted with each halogen.

### Step-by-Step Solution:

1. **Understand the Reactants and Products**:
- The reactant is hydrogen sulfide (H₂S).
- The product we are interested in is elemental sulfur (S).

2. **Identify the Halogens**:
- The halogens given in the options are Cl₂ (chlorine), F₂ (fluorine), and Br₂ (bromine).

3. **Determine the Oxidation State of Sulfur in H₂S**:
- In H₂S, sulfur (S) has an oxidation state of -2.

4. **Reactions with Each Halogen**:
- **With Chlorine (Cl₂)**:
- Reaction: H₂S + Cl₂ → 2 HCl + S
- In this reaction, sulfur is oxidized from -2 in H₂S to 0 in elemental sulfur (S). Thus, Cl₂ can oxidize H₂S.

- **With Fluorine (F₂)**:
- Reaction: H₂S + 6 F₂ → 6 HF + S
- Here, sulfur is oxidized from -2 in H₂S to +6 in SF₆. Thus, F₂ can also oxidize H₂S.

- **With Bromine (Br₂)**:
- Reaction: H₂S + Br₂ → 2 HBr + S
- In this case, sulfur is oxidized from -2 in H₂S to 0 in elemental sulfur (S). Thus, Br₂ can oxidize H₂S as well.

5. **Conclusion**:
- All three halogens (Cl₂, F₂, Br₂) can oxidize H₂S to sulfur. Therefore, the correct answer is **option D: all of these**.