Among the nitrate of alkali metals which one can be decomposed to its oxide on strong heating?

Options

A. `NaNO_(3)`
B. `KNO_(3)`
C. `LiNO_(3)`
D. All of these

Answer

To determine which alkali metal nitrate can be decomposed to its oxide upon strong heating, we will analyze the decomposition reactions of the nitrates of the alkali metals: sodium nitrate (NaNO3), potassium nitrate (KNO3), and lithium nitrate (LiNO3).

### Step-by-Step Solution:

1. **Identify the Nitrates**: The nitrates of alkali metals we will consider are:
- Sodium nitrate (NaNO3)
- Potassium nitrate (KNO3)
- Lithium nitrate (LiNO3)

2. **Decomposition of Sodium Nitrate (NaNO3)**:
- When sodium nitrate is heated strongly, it decomposes as follows:
\[ 2 \text{NaNO}_3 \rightarrow 2 \text{NaNO}_2 + \text{O}_2 \]
- This reaction produces sodium nitrite (NaNO2) and oxygen gas (O2).
- **Conclusion**: Sodium nitrate does not decompose to its oxide.

3. **Decomposition of Potassium Nitrate (KNO3)**:
- Upon strong heating, potassium nitrate decomposes as follows:
\[ 2 \text{KNO}_3 \rightarrow 2 \text{KNO}_2 + \text{O}_2 \]
- This reaction yields potassium nitrite (KNO2) and oxygen gas (O2).
- **Conclusion**: Potassium nitrate also does not decompose to its oxide.

4. **Decomposition of Lithium Nitrate (LiNO3)**:
- When lithium nitrate is subjected to strong heating, it decomposes as follows:
\[ 4 \text{LiNO}_3 \rightarrow 2 \text{Li}_2\text{O} + 4 \text{NO}_2 + \text{O}_2 \]
- This reaction results in the formation of lithium oxide (Li2O), nitrogen dioxide (NO2), and oxygen gas (O2).
- **Conclusion**: Lithium nitrate can be decomposed to its oxide.

5. **Final Answer**: Among the nitrates of alkali metals, **lithium nitrate (LiNO3)** can be decomposed to its oxide (Li2O) upon strong heating.