`S^(2-)` and `SO_(3)^(2-)` ions can be distinguished by using

Options

A. `(CH_(3)COO)_(2) Pb`
B. `Na_(2) [Fe(CN)_(5) NO]`
C. Both (a) & (b)
D. None of these

Explanation

To distinguish between the `S^(2-)` (sulfide ion) and `SO3^(2-)` (sulfite ion), we can use specific reagents that will react differently with each ion. Here’s a step-by-step solution:

### Step 1: Identify the Reagents
The reagents we will use to distinguish between the two ions are Lead Acetate (Pb(CH3COO)2) and Sodium Pentacyanoferrate(II) (Na2[Fe(CN)5NO]).

### Step 2: Reaction with Lead Acetate
1. **For `S^(2-)` (sulfide ion)**: When we add Lead Acetate to a solution containing `S^(2-)`, a black precipitate of Lead Sulfide (PbS) is formed.
- **Reaction**:
\[ Pb(CH3COO)2 + S^{2-} \rightarrow PbS (s) + 2 CH3COO^{-} \]
- **Observation**: The formation of a black precipitate indicates the presence of sulfide ions.

2. **For `SO3^(2-)` (sulfite ion)**: When Lead Acetate is added to a solution containing `SO3^(2-)`, a white precipitate of Lead Sulfate (PbSO4) is formed.
- **Reaction**:
\[ Pb(CH3COO)2 + SO3^{2-} \rightarrow PbSO4 (s) + 2 CH3COO^{-} \]
- **Observation**: The formation of a white precipitate indicates the presence of sulfite ions.

### Step 3: Reaction with Sodium Pentacyanoferrate(II)
1. **For `S^(2-)` (sulfide ion)**: When we add Sodium Pentacyanoferrate(II) to a solution containing `S^(2-)`, a violet-colored complex is formed.
- **Reaction**:
\[ Na2[Fe(CN)5NO] + S^{2-} \rightarrow Na4[Fe(CN)5NO] (violet) \]
- **Observation**: The appearance of a violet color indicates the presence of sulfide ions.

2. **For `SO3^(2-)` (sulfite ion)**: When Sodium Pentacyanoferrate(II) is added to a solution containing `SO3^(2-)`, no specific color change occurs, and the solution remains colorless.
- **Reaction**:
\[ Na2[Fe(CN)5NO] + SO3^{2-} \rightarrow Na4[Fe(CN)5NO.SO3] (colorless) \]
- **Observation**: The absence of a violet color indicates the presence of sulfite ions.

### Conclusion
By using Lead Acetate and Sodium Pentacyanoferrate(II), we can effectively distinguish between `S^(2-)` and `SO3^(2-)` ions based on the color of the precipitate or solution formed.