Kolbe's electrolysis involves electrolysis of concentrated sodium/potassium salts of carboxylic acids. At anode, decarboxylation occurs producing alkane (for monocarboxylic acids) and CO₂. At cathode, H₂ gas evolves via reduction of H₂O, increasing OH^- concentration and thus pOH. For maleic acid (HOOC-CH=CH-COOH), electrolysis gives acetylene (ethyne) as major product. All statements are correct except: "When salt of maleic acid is used then ethyne will be major product" is incorrect - maleic acid electrolysis actually yields acetylenedicarboxylic acid, not ethyne.

Final answer: "When salt of maleic acid is used then ethyne will be major product" is the incorrect statement.