Using dil HCI, which of the following radical cannot be confirmed

Options

A. `S^(2-)`
B. `S_(2)O_(3)^(2-)`
C. `CO_(3)^(2-)`
D. `NO_(2)^(Θ)`

Explanation

To determine which radical cannot be confirmed using dilute HCl, we will analyze the reactions of each given radical with dilute HCl.

### Step-by-Step Solution:

1. **Identify the radicals**: The question provides four radicals to analyze:
- S²⁻ (sulfide ion)
- S₂O₃²⁻ (thiosulfate ion)
- CO₃²⁻ (carbonate ion)
- NO₂⁻ (nitrite ion)

2. **Reaction of S²⁻ with dilute HCl**:
- When sulfide ion (S²⁻) reacts with dilute HCl, it produces hydrogen sulfide gas (H₂S), which has a characteristic smell of rotten eggs.
- **Equation**:
\[ \text{S}^{2-} + 2 \text{HCl} \rightarrow \text{H}_2\text{S} + 2 \text{Cl}^- \]
- **Conclusion**: The sulfide ion can be confirmed due to the distinct smell of H₂S.

3. **Reaction of S₂O₃²⁻ with dilute HCl**:
- The thiosulfate ion (S₂O₃²⁻) reacts with dilute HCl to produce sulfur dioxide (SO₂), which has a suffocating smell, and may also produce a yellow or white precipitate of sulfur.
- **Equation**:
\[ \text{S}_2\text{O}_3^{2-} + 2 \text{HCl} \rightarrow \text{SO}_2 + \text{S} + 2 \text{Cl}^- + \text{H}_2\text{O} \]
- **Conclusion**: The thiosulfate ion can be confirmed due to the smell of SO₂ and the formation of precipitate.

4. **Reaction of CO₃²⁻ with dilute HCl**:
- The carbonate ion (CO₃²⁻) reacts with dilute HCl to produce carbon dioxide (CO₂), which is odorless, along with water and chloride ions.
- **Equation**:
\[ \text{CO}_3^{2-} + 2 \text{HCl} \rightarrow \text{CO}_2 + \text{H}_2\text{O} + 2 \text{Cl}^- \]
- **Conclusion**: The carbonate ion cannot be confirmed because the gas evolved (CO₂) is odorless, and it produces similar results for bicarbonates.

5. **Reaction of NO₂⁻ with dilute HCl**:
- The nitrite ion (NO₂⁻) reacts with dilute HCl to produce nitrous acid (HNO₂), which decomposes to form nitrogen dioxide (NO₂), a brown gas.
- **Equation**:
\[ \text{NO}_2^{-} + \text{HCl} \rightarrow \text{HNO}_2 + \text{Cl}^- \rightarrow \text{NO} + \text{NO}_2 \text{ (brown gas)} \]
- **Conclusion**: The nitrite ion can be confirmed due to the formation of the brown gas (NO₂).

### Final Conclusion:
The radical that **cannot be confirmed** using dilute HCl is the **carbonate ion (CO₃²⁻)**, as it produces an odorless gas (CO₂) and does not provide a distinct test.

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