2KClO3 + H2C2O4 + H2SO4 K2SO4 + 2CO2 + 2ClO2 + 2H2O
Potassium chlorate react with oxalic acid and sulfuric acid to produce potassium sulfate, carbon dioxide, chlorine dioxide and water. Sulfuric acid - diluted solution. This reaction takes place at a temperature near 90°C.