Question
Give a brief account of Kolbe's electrolysis.
Solution
Kolbe's electrolysis: When concentrated aqueous solution of sodium or potassium salt of the monocarboxylic acid is subjected to electrolysis, the alkane is evolved at the anode.
On passing electricity, the ions will move towards the respective electrodes.
At anode: The electron releasing tendency of CH3COO- ions is more and these are discharged in preference to OH- ions.
At cathode: The electron accepting tendency of H+ ions is more and these are discharged in preference to Na+ ions which remain in solution.
Limitations:
(i) Only alkanes with an even number of carbon atoms can be formed.
(ii) Methane cannot be prepared by this method.
