Question

Balance the equation by oxidation number method when potassium permanganate reacts with ferrous sulphate in presence of sulphuric acid to form potassium sulphate, ferric sulphate, manganese sulphate & water.​

Answer 1

Answer:

3

Down vote

Your first half reaction, for the reduction, is correct:

10e−+10H++2KMnO4+3H2SO4⟶K2SO4+2MnSO4+8H2O(1)

For the second half reaction, the oxidation, start by balancing iron:

FeSO42FeSO4⟶Fe2(SO4)3⟶Fe2(SO4)3(2a)(2b)

Add H2SO4 on the left so you can balance sulfur:

2FeSO4H2SO4+2FeSO4⟶Fe2(SO4)3⟶Fe2(SO4)3(2c)(2d)

Now balance the protons and electrons:

H2SO4+2FeSO4H2SO4+2FeSO4⟶Fe2(SO4)3⟶Fe2(SO4)3+2H++2e−(2d)(2e)

Now add (1) and five times (2e) so that the electrons are equal on every side and coincidentally the protons also balance:

10e−+10H++2KMnO4+3H2SO45H2SO4+10FeSO4⟶K2SO4+2MnSO4+8H2O⟶5Fe2(SO4)3+10H++10e−(1)(5×2e)