Which of the following cation does not give precipitate with `H_(2)S` in neutral medium?

Options

A. `Fe^(3+)`
B. `Cu^(2+)`
C. `Bi^(3+)`
D. `Ag^(+)`

Explanation

To determine which cation does not give a precipitate with hydrogen sulfide (H₂S) in a neutral medium, we will analyze the reactions of the given cations with H₂S one by one.

### Step-by-Step Solution:

1. **Identify the Cations**: The cations provided in the question are:
- Fe³⁺ (Iron III)
- Co²⁺ (Cobalt II)
- Bi³⁺ (Bismuth III)
- Ag⁺ (Silver)

2. **Reaction of Fe³⁺ with H₂S**:
- When Fe³⁺ reacts with H₂S, it does not form a precipitate. Instead, it can be reduced to Fe²⁺ and sulfur is produced.
- **Equation**: Fe³⁺ + H₂S → Fe²⁺ + S (no precipitate)

3. **Reaction of Co²⁺ with H₂S**:
- Co²⁺ reacts with H₂S to form cobalt sulfide (CoS), which is a precipitate.
- **Equation**: Co²⁺ + H₂S → CoS (precipitate)

4. **Reaction of Bi³⁺ with H₂S**:
- Bi³⁺ reacts with H₂S to form bismuth sulfide (Bi₂S₃), which is also a precipitate.
- **Equation**: 2 Bi³⁺ + 3 H₂S → Bi₂S₃ + 6 H⁺ (precipitate)

5. **Reaction of Ag⁺ with H₂S**:
- Ag⁺ reacts with H₂S to form silver sulfide (Ag₂S), which is a precipitate.
- **Equation**: 2 Ag⁺ + H₂S → Ag₂S + 2 H⁺ (precipitate)

6. **Conclusion**:
- Among the cations analyzed, only Fe³⁺ does not form a precipitate with H₂S in a neutral medium. The other cations (Co²⁺, Bi³⁺, and Ag⁺) all form precipitates.

### Final Answer:
The cation that does not give a precipitate with H₂S in neutral medium is **Fe³⁺** (Iron III).

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