Which of the following will release `CO_(2)` when heated to `1000^(@)C`?

Options

A. `KHCO_(3)`
B. `Li_(2)CO_(3)`
C. `K_(2)CO_(3)`
D. `PbCO_(3)`

Answer

To determine which of the given compounds will release CO2 when heated to 1000°C, we will analyze the thermal decomposition reactions of each compound. The compounds to consider are KHCO3, Li2CO3, K2CO3, and PbCO3.

### Step-by-Step Solution:

1. **Analyze KHCO3 (Potassium Bicarbonate)**:
- When KHCO3 is heated, it decomposes as follows:
\[ 2 \, KHCO_3 \rightarrow K_2CO_3 + CO_2 + H_2O \]
- This reaction shows that KHCO3 releases CO2 upon heating.

2. **Analyze Li2CO3 (Lithium Carbonate)**:
- When Li2CO3 is heated, it decomposes as follows:
\[ Li_2CO_3 \rightarrow Li_2O + CO_2 \]
- This reaction indicates that Li2CO3 also releases CO2 when heated.

3. **Analyze K2CO3 (Potassium Carbonate)**:
- When K2CO3 is heated, it does not release CO2. Instead, it decomposes as follows:
\[ 2 \, K_2CO_3 \rightarrow 2 \, KCO + O_2 \]
- This shows that K2CO3 does not produce CO2 upon heating.

4. **Analyze PbCO3 (Lead Carbonate)**:
- When PbCO3 is heated, it decomposes as follows:
\[ PbCO_3 \rightarrow PbO + CO_2 \]
- This reaction indicates that PbCO3 releases CO2 when heated.

### Conclusion:
The compounds that release CO2 when heated to 1000°C are:
- KHCO3
- Li2CO3
- PbCO3

The compound that does not release CO2 is K2CO3.

### Final Answer:
**KHCO3, Li2CO3, and PbCO3 will release CO2 when heated to 1000°C.**