Reaction of acetic acid with sodium bicarbonate, gives `CO_2`. The presence of `CO_2` comes from

Options

A. HCO_3^-` group
B. `H-CH_3`from methylene group
C. `-CH_3 "group of" CH_3COOH`
D. `-COOH"group in"CH_3COOH`

Answer

To solve the question regarding the reaction of acetic acid with sodium bicarbonate that produces carbon dioxide (CO₂), we can break it down into a series of steps.

### Step-by-Step Solution:

1. **Identify the Reactants**: The reactants in this reaction are acetic acid (CH₃COOH) and sodium bicarbonate (NaHCO₃).

2. **Write the Balanced Chemical Equation**: The reaction can be represented as follows:
\[ \text{CH}_3\text{COOH} + \text{NaHCO}_3 \rightarrow \text{CH}_3\text{COONa} + \text{CO}_2 + \text{H}_2\text{O} \]
Here, acetic acid reacts with sodium bicarbonate to produce sodium acetate, carbon dioxide, and water.

3. **Understand the Source of CO₂**: The carbon dioxide produced in this reaction primarily comes from the bicarbonate ion (HCO₃⁻) present in sodium bicarbonate. When sodium bicarbonate dissociates, it can release carbon dioxide gas.

4. **Dissociation of Sodium Bicarbonate**: The dissociation of sodium bicarbonate can be represented as:
\[ \text{NaHCO}_3 \rightarrow \text{Na}^+ + \text{HCO}_3^- \]
The bicarbonate ion (HCO₃⁻) can further dissociate to produce carbon dioxide:
\[ \text{HCO}_3^- \rightarrow \text{CO}_2 + \text{OH}^- \]

5. **Conclusion**: Therefore, the presence of CO₂ in the reaction comes from the bicarbonate ion (HCO₃⁻) that decomposes to release CO₂ gas.

### Final Answer:
The presence of CO₂ comes from the bicarbonate ion (HCO₃⁻) in sodium bicarbonate.