For the preparation of alkanes, aqueous solution of sodium or potassium salt of carboxylic acid
is subjected to

This is Kolbe's electrolytic method which produces alkanes
\(2 \mathrm{RCOON} a+2 \mathrm{H}_{2} \mathrm{O}\) Electrolysis
\(2 {\mathrm{R}} {-\mathrm{R}+2 \mathrm{~N} \mathrm{aOH}} +\mathrm{H}_{2}+\mathrm{CO}_{2}\)
Steps of reaction:
\(2 \mathrm{CH}_{3} \mathrm{COON} a \stackrel{\text { Ionization }}{\rightleftharpoons} 2 \mathrm{CH}_{3} \mathrm{COO}^{-}+2 \mathrm{Na}^{+}\) \(2 \mathrm{H}_{2} \mathrm{O} \stackrel{\text { Ionization }}{\rightleftharpoons} 2 \mathrm{OH}^{-}+2 \mathrm{H}^{+}\)
At anode:
\(2 \mathrm{CH}_{3} \mathrm{COO}^{-}-2 e^{-} \rightarrow\left[2 \mathrm{CH}_{3} \mathrm{COO}\right] \rightarrow \mathrm{CH}_{3}-\mathrm{CH}_{3}+2 \mathrm{CO}_{2}\)
At cathode: \(2 \mathrm{H}^{+}+2 e^{-} \rightarrow[2 \mathrm{H}] \rightarrow \mathrm{H}_{2}\)