When washing soda is heated

Options

A. CO is released
B. CO+`CO_(2)` is released
C. `CO_(2)` is released
D. Water vapour is released.

Explanation

To solve the question "When washing soda is heated," we need to understand the composition of washing soda and the changes that occur upon heating.

### Step-by-Step Solution:

1. **Identify Washing Soda**:
- Washing soda is chemically known as sodium carbonate decahydrate, represented as Na2CO3·10H2O. This means it contains sodium carbonate (Na2CO3) along with 10 molecules of water of crystallization.

2. **Heating Washing Soda**:
- When washing soda is heated, the water of crystallization begins to evaporate. The first step involves the removal of 9 water molecules.
- The reaction can be represented as:
\[ \text{Na}_2\text{CO}_3 \cdot 10\text{H}_2\text{O} \xrightarrow{\text{heat}} \text{Na}_2\text{CO}_3 \cdot 9\text{H}_2\text{O} + \text{H}_2\text{O} \]
- Here, one molecule of water is released, leaving behind Na2CO3·9H2O.

3. **Further Heating**:
- If the heating continues, the remaining water molecules will also be removed. Further heating will lead to the complete removal of the remaining water of crystallization.
- This can be represented as:
\[ \text{Na}_2\text{CO}_3 \cdot 9\text{H}_2\text{O} \xrightarrow{\text{heat}} \text{Na}_2\text{CO}_3 + 9\text{H}_2\text{O} \]
- In this step, all 9 water molecules are released as water vapor.

4. **Final Conclusion**:
- Therefore, when washing soda is heated, water vapor is released during the process. The final product after complete heating is anhydrous sodium carbonate (Na2CO3).

### Final Answer:
When washing soda is heated, water vapor is released.