Concept:Decarboxylation is the chemical removal of a carboxyl group, releasing carbon dioxide. For simple aliphatic carboxylic acids (usually as their sodium salts), this requires extreme heat and a specialized fluxing agent.
Formula:$$ \text{R-COONa} + \text{NaOH} \xrightarrow{\text{CaO, } \Delta} \text{R-H} + \text{Na}_2\text{CO}_3 $$
Solution:- Soda lime is a solid mixture of sodium hydroxide (\( \text{NaOH} \)) and calcium oxide (\( \text{CaO} \)).
- The \( \text{NaOH} \) acts as the active decarboxylating agent, while the \( \text{CaO} \) keeps the mixture porous, prevents it from melting, and mitigates the aggressive nature of molten \( \text{NaOH} \).
Why other options are incorrect:Baking soda (\( \text{NaHCO}_3 \)) only forms a salt; it cannot strip the carbon off the chain. Caustic soda (\( \text{NaOH} \)) alone will melt and damage glassware without the stabilizing lime.
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