When propionic acid is treated with aqueous sodium bicarbonate, `CO_(2)` is liberated. The "C" of `CO_(2)` comes from

Options

A. methyl group
B. carboxylic acid group
C. methylene group
D. bicarbonate

Explanation

To solve the question regarding the liberation of CO₂ when propionic acid reacts with aqueous sodium bicarbonate, we can follow these steps:

### Step 1: Identify the Reactants
The reactants in this reaction are propionic acid (C₂H₅COOH) and sodium bicarbonate (NaHCO₃).

### Step 2: Understand the Reaction Type
This is an acid-base reaction where propionic acid acts as the acid and sodium bicarbonate acts as the base.

### Step 3: Write the Reaction
When propionic acid reacts with sodium bicarbonate, the following reaction occurs:
\[ \text{C}_2\text{H}_5\text{COOH} + \text{NaHCO}_3 \rightarrow \text{C}_2\text{H}_5\text{COONa} + \text{H}_2\text{CO}_3 \]

Here, sodium propionate (C₂H₅COONa) is formed along with carbonic acid (H₂CO₃).

### Step 4: Decomposition of Carbonic Acid
The carbonic acid (H₂CO₃) formed is unstable and decomposes into water (H₂O) and carbon dioxide (CO₂):
\[ \text{H}_2\text{CO}_3 \rightarrow \text{H}_2\text{O} + \text{CO}_2 \]

### Step 5: Identify the Source of Carbon in CO₂
The carbon atom in the carbon dioxide (CO₂) that is liberated comes from the bicarbonate ion (HCO₃⁻) present in sodium bicarbonate.

### Conclusion
Thus, the carbon in the CO₂ that is liberated during the reaction comes from the sodium bicarbonate (NaHCO₃).

### Final Answer
The "C" of CO₂ comes from sodium bicarbonate (NaHCO₃).

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