step by step balancing of redox reaction KClO3+H2SO4 --KHSO4+HClO4+ClO2+H2O ionic equation :- ClO3^-1 ---------- Clo4^-1 + ClO2

step by step balancing of  redox reaction

KClO3+H2SO4  -->KHSO4+HClO4+ClO2+H2O

ionic equation :-

ClO3^-1  ----------> Clo4^-1 + ClO2

oxidation reaction :- 

oxidation number of Cl in Clo3^-1  is +5 and oxidation  number of Clorine in Clo4^-1 is +7 

here oxidation number of clorine is increasing so its a oxidation reaction 

ClO3^-1  -----> ClO4^-1  

Balance the oxidation reaction by adding the electron 

ClO3^-1  -----> ClO4^-1 + 2e^-1  -------------(1)

(oxidation number of clorine is changing + 5 to + 7 so add 2 electron there to balance the reaction )

reduction reaction :-

oxidation number of Clrine in ClO3^-1 is +5 and in ClO2 oxidation number is +4, oxidation number is decreasing  hence this is 

a reduction reaction 

ClO3^-1 ------> ClO2 

ClO3^-1 + e^-1 -------> ClO2     -------------(2)

(oxidation number of clorine is changing + 5 to + 4 so add 1 electron there to balance the reaction )

multiply by 2 in second equation to make same number of electron in both equation first and second 

2ClO3^-1 + 2e^-1 -------> 2ClO2  -------------(3)

add equation first and third we get 

ClO3^-1 + 2ClO3^-1 + 2e^-1  ----------> Clo4^-1 + 2ClO2  + 2e^-1

calcel out the electron we get 

ClO3^-1 + 2ClO3^-1 ----------> Clo4^-1 + 2ClO2 

H2SO4 is an acid and in acidic redox reaction we always balance the reaction using H+ ions

So balance the charge using H+ ions 

ClO3^-1 + 2ClO3^-1 + 2H+ ----------> Clo4^-1 + 2ClO2 

now Add H2O to balance the complete reaction 

ClO3^-1 + 2ClO3^-1 + 2H+ ----------> Clo4^-1 + 2ClO2 + H2O

Answer :-

               3ClO3^-1 + 2H+ ----------> Clo4^-1 + 2ClO2 + H2O