`HCOONa underset(heat)to X+H_(2)`. X is

Options

A. `Na_(2)CO_(3)`
B. `CO_(2)`
C. `(COONa)_(2)`
D. CO

Answer

To solve the question, we need to analyze the thermal decomposition of sodium formate (HCOONa) when heated. The reaction can be broken down into several steps:

### Step 1: Understand the Compound
Sodium formate (HCOONa) is the sodium salt of formic acid (HCOOH). When heated, it undergoes thermal decomposition.

### Step 2: Write the Decomposition Reaction
When sodium formate is heated, it decomposes to produce carbon dioxide (CO₂) and sodium hydroxide (NaOH) initially, but in the presence of heat, it further decomposes to produce hydrogen gas (H₂) and carbon monoxide (CO).

The overall reaction can be represented as:
\[ 2 \text{HCOONa} \xrightarrow{\text{heat}} \text{H}_2 + \text{CO} + \text{Na}_2\text{CO}_3 \]

### Step 3: Identify the Product X
From the decomposition reaction, we can see that one of the products formed is hydrogen gas (H₂). Therefore, in the equation given in the question, X corresponds to hydrogen gas (H₂).

### Conclusion
Thus, the answer to the question is:
**X is H₂ (hydrogen gas)**.

---