In thed disproportionation reaction, 3HClO3→HClO4 + Cl2+ 2O2+H2O, the equivalent mass of the oxidising agent is (molar mass of HClO3 = 84.45)

2HClO3+5→HClO+7+Cl20+2O2+H2OSince O.N of Cl decreases from +5 in HClO3 to zero in Cl2 therefore, HClO3 acts as the oxidising agent. In other words, O.no decreases by 5 and the equivalent mass of oxidising agent =Mol mass/5 = 84.45/5 = 16.89.