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what is Kolbe's electrolytic method?

Kolbe's electrolysis : Aqueous solution of alkali salts of carboxylic acids upon electrolysis give alkanes.

    RCOONa(aq)       ?      2RCOO^- + 2Na⁺

At anode : 2RCOO^-  ?          R - R        +   2CO₂  +  2e^-

   Carboxylate ion                   alkane

At cathode  :  2Na+ +2e-   ?    2Na

                     2Na   +2H₂O ? 2NaOH  +H₂

          2H ⁺   +  2e^-   ?  H₂(g)  +H₂

Thus ,the solution around cathode becomes alkaline due to the accumulation of the OH^- ions .