Name the gas evolved in each of the following cases : Action of heat on washing soda.

Explanation

**Step-by-Step Solution:**

1. **Identify the Compound**: The compound in question is washing soda, which is chemically known as sodium carbonate decahydrate. Its chemical formula is Na2CO3·10H2O.

2. **Understand the Process**: The question asks about the action of heat on washing soda. When washing soda is heated, it undergoes a thermal decomposition reaction.

3. **Heating Washing Soda**: When sodium carbonate decahydrate is strongly heated, the water of crystallization (the 10H2O part) is released as water vapor.

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