Question

Why doesn't potassium ion K+ from KMnO4 appear in the following two unbalanced equations: MnO4– + C2O42– Mn2+ + CO2
MnO4– + Fe2+ Mn2+ + Fe3+ ?


A. KMnO4 is not added to either reaction.
B. The presence of K+ would result in a net positive charge in the products.
C. K+ is a spectator ion and redox reactions are written as net ionic reactions.
D. The equations cannot be balanced if the potassium ion K+ is present.
E. None of these.

Answer 1

You REALLY should use arrows. How are we to know which are the reactants and which the products? I know which is which in this case, I think, so here goes.
K^+ is a spectator ion.

Answer 2

C. K+ is a spectator ion and redox reactions are written as net ionic reactions.