Consider the reduction reactions and their equilibrium constants. Cu+(aq)+e−↽−−⇀Cu(s)Pb2+(aq)+2e−↽−−⇀Pb(s)Fe3+(aq)+3e−↽−−⇀Fe(s)????????????=6.2×108=4.0×10−5=9.3×10−3 Cu + ( aq ) + e − ↽ − − ⇀ Cu ( s ) K =6.2× 10 8 Pb 2 + ( aq ) +2 e − ↽ − − ⇀ Pb ( s ) K =4.0× 10 − 5 Fe 3 + ( aq ) +3 e − ↽ − − ⇀ Fe ( s ) K =9.3× 10 − 3 Arrange these ions from strongest to weakest oxidizing agent.
the most reactive metal is the strongest reducing agent but weakest oxidizing agent. And therefore copper being the least reactive turns to be the strongest oxidizing agent followed by iron then lead.