which metal is the stronger reducing agent?

[Smooth Operater]

Based on the following information, which metal is the stronger reducing agent?

Zn2+ + Fe ---> no rxn
Fe2+ + Zn ---> Zn2+ + Fe
Mg2+ + Zn ---> no rxn
Zn2+ + Mg ---> Mg2+ + Zn
Cu2+ + Zn ---> Cu + Zn2+

A. Cu
B. Fe
C. Mg
D. Zn
E. all metals are oxidizing agent

The correct answer is C. But how can you arrive to this answer ?? I am kinda clueless, I know reducing agent perfer to become Cations. thanks

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[GRAD]

the strongest reducing agent is the one that gets oxidized the most......that means it loses electrons

 

[Smooth Operater]

yeAH, i know that. but how would you figure out this problem with known definiation?

 

[cryptozoologist]

Based on the following information, which metal is the stronger reducing agent?

Zn2+ + Fe ---> no rxn
Fe2+ + Zn ---> Zn2+ + Fe
Mg2+ + Zn ---> no rxn
Zn2+ + Mg ---> Mg2+ + Zn
Cu2+ + Zn ---> Cu + Zn2+

A. Cu
B. Fe
C. Mg
D. Zn
E. all metals are oxidizing agent

The correct answer is C. But how can you arrive to this answer ?? I am kinda clueless, I know reducing agent perfer to become Cations. thanks

Zn gives electrons in all cases except the Mg equations. zinc is a strong reducing agent because in most of the reactions above that go forward, it gets oxidized (loses electrons.) There is only one case above that demonstrates a stronger reducing agent than zinc: Mg. when you react Zn with Mg2+, nothing happens, so Mg2+ doesn't get oxidized or reduced.

If you react Mg with Zn2+, then the reaction goes because Mg will get oxidized and donate it's electrons to Zn2+. So while all equations above show zinc as the reducing agent, the equations with Mg show Mg as the reducing agent.

Thus Mg is a stronger reducing agent.

Secondarily and qualitatively, you can remember that alkaline earth and alkaline metals both give up their electrons easily (have low electron affinity) and can be considered to have good reducing strength....alternatively, halogens have great oxidizing strength by the same logic.