Concept:Carboxylic acids react with sodium carbonate to form a sodium carboxylate salt, carbon dioxide, and water.
Formula:$$ 2\text{CH}_3\text{CH}_2\text{COOH (X)} + \text{Na}_2\text{CO}_3 \longrightarrow 2\text{CH}_3\text{CH}_2\text{COONa (Y)} + \text{CO}_2 + \text{H}_2\text{O} $$
Solution:- The question stem technically asks for "Compound Y", which should be sodium propanoate (\( \text{CH}_3\text{CH}_2\text{COONa} \)).
- However, none of the options list a salt. The official past-paper key assigns Option D.
- Therefore, Option D (Propanoic acid) represents "Compound X" (the reactant acid), which is the only molecule among the choices logically capable of reacting with a carbonate to release \( \text{CO}_2 \).
Why other options are incorrect:Alkenes, esters, and aldehydes do not undergo acid-base neutralization with sodium carbonate to evolve carbon dioxide.
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