During Kolbe's electrolysis hydrocarbons with even number of C-atoms are because Kolbe's electrolysis occurs as follows : At anode At cathode 2H2O+2e−⟶2OH−+2H∘ 2H∘⟶H2(g)
For example, In case of alkenes
As hydrocarbons are obtained by Kolbe's electrolysis via combination of two alkyl groups (i.e. R−R ). Thus, it always give hydrocarbons in which C-atoms are present in even number at anode.