Find number of species which produce elemental sulphur when
treated with `H_(2)S,`
`Fe^(2+), SO_(2), H_(2)O, O_(3), HNO_(3)`

Explanation

To find the number of species that produce elemental sulfur when treated with H₂S, we will analyze each species one by one.

### Step-by-Step Solution:

1. **Species: Fe²⁺**
- Reaction: Fe²⁺ + H₂S → FeS + 2H⁺
- Analysis: This reaction produces iron sulfide (FeS) and does not produce elemental sulfur.
- Conclusion: **Does not produce elemental sulfur.**

2. **Species: SO₂**
- Reaction: SO₂ + 2H₂S → 3S + 2H₂O
- Analysis: This reaction produces elemental sulfur (S) along with water.
- Conclusion: **Produces elemental sulfur.**

3. **Species: H₂O₂**
- Reaction: H₂O₂ + H₂S → S + 2H₂O
- Analysis: This reaction produces elemental sulfur (S) and water.
- Conclusion: **Produces elemental sulfur.**

4. **Species: O₃**
- Reaction: O₃ + H₂S → S + H₂O + O₂
- Analysis: This reaction produces elemental sulfur (S), water, and oxygen.
- Conclusion: **Produces elemental sulfur.**

5. **Species: HNO₃**
- Reaction: HNO₃ + 3H₂S → 3S + 3H₂O + 2NO₂
- Analysis: This reaction produces elemental sulfur (S) along with water and nitrogen dioxide.
- Conclusion: **Produces elemental sulfur.**

### Summary of Results:
- Fe²⁺: Does not produce elemental sulfur.
- SO₂: Produces elemental sulfur.
- H₂O₂: Produces elemental sulfur.
- O₃: Produces elemental sulfur.
- HNO₃: Produces elemental sulfur.

### Total Count:
Out of the five species, four produce elemental sulfur when treated with H₂S.

### Final Answer:
**The number of species that produce elemental sulfur is 4.**

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