a,

• Chất khử: Fe (sắt) bị oxi hóa thành Fe^3+ trong Fe(NO3)3.
• Chất oxi hóa: N trong HNO3 bị khử thành NO.

• $$4\text{Fe} + 10\text{HNO}_{3} \rightarrow 4\text{Fe(NO}_{3}\text{)}_{3} + 2\text{NO} + 4\text{H}_{2}\text{O}$$4Fe+10HNO3​→4Fe(NO3​)3​+2NO+4H202

• b,

• Chất khử: Fe^2+ trong FeSO4 bị oxi hóa thành Fe^3+ trong Fe2(SO4)3.
• Chất oxi hóa: MnO4^- bị khử thành Mn^2+ trong MnSO4.

• $$2\text{KMnO}_{4} + 10\text{FeSO}_{4} + 8\text{H}_{2}\text{SO}_{4} \rightarrow 5\text{Fe}_{2}(\text{SO}_{4})_{3} + 2\text{MnSO}_{4} + 2\text{K}_{2}\text{SO}_{4} + 8\text{H}_{2}\text{O}$$2KMnO4​+10FeSO4​+8H2​SO4​→5Fe2​(SO4​)3​+2MnSO4​+2K2​SO4​+8H2​O

•  
• $$2\text{KMnO}_{4} + 10\text{FeSO}_{4} + 8\text{H}_{2}\text{SO}_{4} \rightarrow 5\text{Fe}_{2}(\text{SO}_{4})_{3} + 2\tet{MnSO}_{4} + 2\text{K}_{2}\text{SO}_{4} + 8\text{H}_{2}\text{O}$$$$2\text{KMnO}_{4} + 10\text{FeSO}_{4} + 8\text{H}_{2}\text{SO}_{4} \rightarrow 5\text{Fe}_{2}(\text{SO}_{4})_{3} + 2\text{MnSO}_{4} + 2\text{K}_{2}\text{SO}_{4} + 8\text{H}_{2}\text{O}$$$$2\text{KMnO}_{4} + 10\text{FeSO}_{4} + 8\text{H}_{2}\text{SO}_{4} \rightarrow 5\text{Fe}_{2}(\text{SO}_{4})_{3} + 2\text{MnSO}_{4} + 2\text{K}_{2}\text{SO}_{4} + 8\text{H}_{2}\text{O}$$

a,2KMno4 +3H2SO4 + 5CaC2O4  -> 2MnSO4 +K2SO4 + 5CaSO4 +10CO2 + 8H20 

b, 9,998mg/100mL

-82,15 kj/mol