Răspuns:
2FeSO4 + H2O2 +H2SO4 => Fe2(SO4) 3 +2H2O
2 Fe²- 2 e- => 2 FeI³ (oxidare agent reducator )
2 O-¹+ 2 e- => 2 O-²(reducereagent oxidant )
S+2H2SO4=>3SO2 + 2H2O
S⁰ - 4 e- => S⁴(oxidare agent reducator )
2 S⁶+ 4 e- => 2 S⁴(reducere agent oxidant)