Assertion: Sodium carbonate can be obtained by heating baking soda.
Reason: Recrystallisation of sodium carbonate gives washing soda.
Choose the correct answer from the following options.
Answer & explanation
Correct answer: option 2
The correct answer is option 2. Both Assertion and Reason are correct, and Reason is not the correct explanation of Assertion.
Sodium carbonate can indeed be obtained by heating baking soda (sodium bicarbonate). The chemical reaction is: \[ 2 \text{NaHCO}_3 \rightarrow \text{Na}_2\text{CO}_3 + \text{H}_2\text{O} + \text{CO}_2 \]
- Recrystallization of sodium carbonate does not directly give washing soda (sodium carbonate decahydrate, Na₂CO₃·10H₂O). The formation of washing soda involves further crystallization in the presence of water and sodium carbonate decahydrate forms under specific conditions.