On heating anhydrous `Na_(2)CO_(3),.....` is evolved

Options

A. `CO_(2)`
B. Water vapour
C. CO
D. No gas

Explanation

To solve the question regarding the heating of anhydrous Na₂CO₃ (sodium carbonate) and what gas is evolved, we can follow these steps:

### Step 1: Understand the Nature of Na₂CO₃
Anhydrous sodium carbonate (Na₂CO₃) is known to be thermally stable. This means that when it is heated, it does not decompose into other substances.

**Hint:** Remember that thermally stable compounds do not break down into simpler substances when heated.

### Step 2: Analyze the Heating Process
When Na₂CO₃ is heated, it does not undergo decomposition. Unlike other carbonates, such as calcium carbonate (CaCO₃), which releases carbon dioxide (CO₂) upon heating, Na₂CO₃ remains intact.

**Hint:** Consider the behavior of different carbonates when subjected to heat. Not all carbonates behave the same way.

### Step 3: Identify the Products of Heating
Since Na₂CO₃ does not decompose, there are no gaseous products formed during the heating process. Therefore, no gas is evolved when anhydrous sodium carbonate is heated.

**Hint:** Think about what happens to a substance that is thermally stable; it should not produce any gases.

### Conclusion
On heating anhydrous Na₂CO₃, no gas is evolved. The correct answer to the question is that there is no gas released during the heating of Na₂CO₃.

**Final Answer:** No gas is evolved when heating anhydrous Na₂CO₃.