For first case The reaction is as follows, Cl2+SO2+2H2O→H2SO4+2HCl Calculate the oxidation number of sulphur in H2SO4 2+x+4(−2)=0 x+2−8=0 x=+6 For second case The reaction is as follows, 5Cl2+I2+6H2O→2HIO3+10HCl Calculate the oxidation number of I in HIO3 1+x+3(−2)=0 x+1−6=0 x=+5