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DECARBOXYLATION refers to the loss of $\mathrm{CO_2}$ from a carboxylic acid (or its salt). When sodium acetate is HEATED with soda lime ($\mathrm{NaOH}$ + $\mathrm{CaO}$), the major organic product is
Aethane ($\mathrm{C_2H_6}$)
Bmethane ($\mathrm{CH_4}$)
Cacetic acid (regenerated)
Dmethanal ($\mathrm{HCHO}$)
Answer & Solution
Correct answer: B. methane ($\mathrm{CH_4}$)
1. NCERT §8.6 (Carboxylic Acids — chemical reactions): heating the sodium SALT of a carboxylic acid with SODA LIME removes CO$_2$.
2. Generic equation: $\mathrm{R{-}COONa} + \mathrm{NaOH} \xrightarrow{\text{CaO},\,\Delta} \mathrm{R{-}H} + \mathrm{Na_2CO_3}$.
3. For sodium acetate, $\mathrm{R} = \mathrm{CH_3}$. So the alkane formed is $\mathrm{CH_3{-}H} = \mathrm{CH_4}$ — METHANE.
4. Equation: $\mathrm{CH_3COONa} + \mathrm{NaOH} \xrightarrow{\text{CaO},\,\Delta} \mathrm{CH_4} + \mathrm{Na_2CO_3}$.
5. Option A is the WURTZ-style coupling product (two methyl radicals joining), which is NOT what soda-lime decarboxylation produces. Option C ignores the reaction. Option D is the partial oxidation product, not what soda lime gives.
6. This is one of the classic laboratory preps of methane.
_Source: NCERT Class 12 Chemistry Part 2, Ch 8, §8.6 (Decarboxylation of carboxylic acid salts), p. 19–20._
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