Which of the following salt liberates a colourless gas on acidification with dil. `H_(2)SO_(4)` ?

Options

A. `KNO_(2)`
B. `Na_(2)CO_(3)`
C. `NaNO_(2)`
D. `NaHCO_(3)`

Answer

To determine which of the following salts liberates a colorless gas upon acidification with dilute sulfuric acid, we will analyze each salt step by step.

**Step 1: Identify the salts provided.**
- The salts given are:
1. Potassium nitrite (KNO2)
2. Sodium carbonate (Na2CO3)
3. Sodium nitrite (NaNO2)
4. Sodium bicarbonate (NaHCO3)

**Step 2: Analyze the reaction of each salt with dilute sulfuric acid.**

1. **Potassium Nitrite (KNO2):**
- Reaction:
\[ KNO_2 + H_2SO_4 \rightarrow K_2SO_4 + NO + H_2O + NO_2 \]
- Gas evolved: Nitrogen dioxide (NO2), which is brown in color.

2. **Sodium Carbonate (Na2CO3):**
- Reaction:
\[ Na_2CO_3 + H_2SO_4 \rightarrow Na_2SO_4 + H_2O + CO_2 \]
- Gas evolved: Carbon dioxide (CO2), which is colorless.

3. **Sodium Nitrite (NaNO2):**
- Reaction:
\[ NaNO_2 + H_2SO_4 \rightarrow Na_2SO_4 + HNO_2 + H_2O \]
- Gas evolved: None.

4. **Sodium Bicarbonate (NaHCO3):**
- Reaction:
\[ NaHCO_3 + H_2SO_4 \rightarrow Na_2SO_4 + H_2O + CO_2 \]
- Gas evolved: Carbon dioxide (CO2), which is colorless.

**Step 3: Conclusion**
- The salts that liberate a colorless gas (CO2) upon acidification with dilute sulfuric acid are:
- Sodium Carbonate (Na2CO3)
- Sodium Bicarbonate (NaHCO3)

Thus, the correct options are Sodium Carbonate and Sodium Bicarbonate.

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