10FeSO410×151.8+2KMnO42×158+8H2SO4→K2SO4+2MnSO4+5Fe2(SO4)3+8H2O
10×151.8 g of FeSO4 require KMnO4=2×158 g
2 g of FeSO4 will require KMnO4=2×158×210×151.8g
Suppose, V mL of KMnO4 solution (0.05 M) is required.
Amount of KMnO4 in this solution =158×0.051000×V
Thus, 158×0.05×V1000=2×158×210×151.8
V=52.7 mL.