Identify the correct statement(s):

Options

A. Sodium carbonate on heating evolves carbon dioxide
B. Sodium nitrate on heating evolves nitrogen dioxide
C. Sodium hydroxide does not decompose on heating
D. Sodium bicarbonate on heating evolve carbon dioxide

Answer

To solve the question of identifying the correct statements regarding sodium compounds, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement 1: Sodium carbonate on heating evolves carbon dioxide.**
- **Analysis:** Sodium carbonate (Na2CO3) exists as decahydrate (Na2CO3·10H2O). When heated, it loses water of crystallization and converts to monohydrated sodium carbonate (Na2CO3·H2O) and then to anhydrous sodium carbonate (Na2CO3). No carbon dioxide (CO2) is evolved during this process.
- **Conclusion:** This statement is **false**.

2. **Statement 2: Sodium nitrate on heating evolves dinitrogen.**
- **Analysis:** Sodium nitrate (NaNO3) decomposes upon heating, producing sodium nitrite (NaNO2) and oxygen (O2), but it does not produce dinitrogen (N2) or nitrogen dioxide (NO2).
- **Conclusion:** This statement is **false**.

3. **Statement 3: Sodium hydroxide does not decompose on heating.**
- **Analysis:** Sodium hydroxide (NaOH) does not decompose when heated. It remains stable under heat. However, it can dissociate into Na⁺ and OH⁻ ions during electrolysis in water.
- **Conclusion:** This statement is **true**.

4. **Statement 4: Sodium bicarbonate on heating evolves carbon dioxide.**
- **Analysis:** Sodium bicarbonate (NaHCO3) decomposes upon heating to form sodium carbonate (Na2CO3), carbon dioxide (CO2), and water (H2O). The reaction can be represented as:
\[ 2 \text{NaHCO}_3 \rightarrow \text{Na}_2\text{CO}_3 + \text{CO}_2 + \text{H}_2\text{O} \]
- **Conclusion:** This statement is **true**.

### Final Conclusion:
The correct statements are:
- Statement 3: Sodium hydroxide does not decompose on heating (True).
- Statement 4: Sodium bicarbonate on heating evolves carbon dioxide (True).