Concept:Carboxylic acids are sufficiently acidic to decompose carbonates and bicarbonates, liberating carbon dioxide gas in the process.
Formula:$$ \text{CH}_3\text{COOH} + \text{NaHCO}_3 \longrightarrow \text{CH}_3\text{COONa} + \text{H}_2\text{O} + \text{CO}_2\uparrow $$
$$ \text{CO}_2 + \text{Ca(OH)}_2 \text{ (lime water)} \longrightarrow \text{CaCO}_3\downarrow \text{ (milky)} + \text{H}_2\text{O} $$
Solution:- Acetic acid reacts with baking soda (\( \text{NaHCO}_3 \)) via a standard acid-base neutralization.
- The breakdown of the resulting carbonic acid rapidly evolves carbon dioxide (\( \text{CO}_2 \)) gas.
- When \( \text{CO}_2 \) is bubbled through lime water (calcium hydroxide), it forms insoluble calcium carbonate, turning the solution milky.
Why other options are incorrect:Hydrogen (\( \text{H}_2 \)) is evolved with active metals, not carbonates, and does not turn lime water milky. \( \text{Cl}_2 \) and \( \text{NO}_2 \) are entirely unrelated to this acid-base reaction.
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