During the reaction of carboxylic acid with `Na_3 CO_3`the carbon dioxide evolved comes from `Na_2 CO_3//`carboxylic acid.

Explanation

To solve the question regarding the reaction of carboxylic acid with sodium carbonate (Na₂CO₃) and the source of the evolved carbon dioxide (CO₂), we can break down the process step by step.

### Step 1: Write the Reaction Equation
The reaction between a carboxylic acid (R-COOH) and sodium carbonate (Na₂CO₃) can be represented as follows:

\[ \text{R-COOH} + \text{Na}_2\text{CO}_3 \rightarrow \text{R-COO}^- \text{Na}^+ + \text{H}_2\text{O} + \text{CO}_2 \]

### Step 2: Identify the Products
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