The alkane formed on heating sodium butanoate with sodalime is

The alkane formed on heating sodium butanoate with sodalime is propane. In this reaction , the product contains one carbon atom less than the carboxylic acid. This process of elimination of carbon dioxide from a carboxylic acid is known as decarboxylation.
$\underset{\mathrm{S}\mathrm{o}\mathrm{d}\mathrm{i}\mathrm{u}\mathrm{m}\mathrm{b}\mathrm{u}\mathrm{t}\mathrm{a}\mathrm{n}\mathrm{o}\mathrm{a}\mathrm{t}\mathrm{e}}{C{H}_{3}C{H}_{2}C{H}_{2}CO{O}^{-}}N{a}^{-}+NaOH\stackrel{CaO}{\underset{\Delta }{\to }}$
$C{H}_{3}C{H}_{2}C{H}_3+N{a}_{2}C{O}_3$