Which of the following compounds decompose on heating ?

Options

A. `NaHCO_(3)`
B. `Na_(2)CO_(3)`
C. `CaCO_(3)`
D. `K_(2)SO_(4)`

Answer

To determine which of the following compounds decompose on heating, we will analyze each compound one by one.

### Step-by-Step Solution:

1. **Identify the Compounds**: The compounds we need to analyze are:
- Sodium hydrogen bicarbonate (NaHCO₃)
- Sodium carbonate (Na₂CO₃)
- Potassium sulfate (K₂SO₄)
- Calcium carbonate (CaCO₃)

2. **Analyze Sodium Hydrogen Bicarbonate (NaHCO₃)**:
- When heated, sodium hydrogen bicarbonate decomposes into sodium carbonate (Na₂CO₃), carbon dioxide (CO₂), and water (H₂O).
- The balanced equation for this decomposition is:
\[ 2 \text{NaHCO}_3 \rightarrow \text{Na}_2\text{CO}_3 + \text{CO}_2 + \text{H}_2\text{O} \]
- **Conclusion**: Sodium hydrogen bicarbonate decomposes on heating.

3. **Analyze Sodium Carbonate (Na₂CO₃)**:
- Sodium carbonate is a stable compound and does not decompose upon heating under normal conditions. It requires very high temperatures to decompose.
- **Conclusion**: Sodium carbonate does not decompose on normal heating.

4. **Analyze Potassium Sulfate (K₂SO₄)**:
- Similar to sodium carbonate, potassium sulfate is also stable and does not decompose on heating under normal conditions. It requires very high temperatures to break down.
- **Conclusion**: Potassium sulfate does not decompose on normal heating.

5. **Analyze Calcium Carbonate (CaCO₃)**:
- When heated, calcium carbonate decomposes into calcium oxide (CaO) and carbon dioxide (CO₂).
- The balanced equation for this decomposition is:
\[ \text{CaCO}_3 \rightarrow \text{CaO} + \text{CO}_2 \]
- **Conclusion**: Calcium carbonate decomposes on heating.

6. **Final Conclusion**:
- From the analysis, the compounds that decompose on heating are:
- Sodium hydrogen bicarbonate (NaHCO₃)
- Calcium carbonate (CaCO₃)

### Answer:
The compounds that decompose on heating are **Sodium hydrogen bicarbonate (NaHCO₃)** and **Calcium carbonate (CaCO₃)**.