10 Fe(NH4)2(SO4)2·6H2O + 2 KMnO4 + 8 H2SO4 -> 5 Fe2(SO4)3 + 2 MnSO4 + K2SO4 + 10 NH4HSO4 + 16 H2O

mole ratio for MnO4^-

From the balanced equation, the mole ratio for KMnO4 is 2.