Question

Consider the following half-reactions: Half-reaction E° (V) I2(s) + 2e- 2I-(aq) 0.535V 2H+(aq) + 2e- H2(g) 0.000V Zn2+(aq) + 2e- Zn(s) -0.763V (1) The weakest oxidizing agent is: Zn2+(aq) enter formula (2) The strongest reducing agent is: Zn(s) (3) The strongest oxidizing agent is: I2(s) (4) The weakest reducing agent is: I-(aq) (5) Will I-(aq) reduce Zn2+(aq) to Zn(s)? (6) Which species can be reduced by H2(g)? If none, leave box blank.

Answer 1

Answer:

The weakest oxidizing agent is Zn^2+(aq)

The strongest reducing agent is Zn(s)

The strongest oxidizing agent is I2(s)

The weakest reducing agent is I^-(aq)

I^- cannot reduce Zn^2+ to Zn(s)

I2(s) can be reduced by hydrogen gas

Explanation:

In looking at oxidizing and reducing agents, our primary guide is the reduction potentials of each specie. The more negative the reduction potential of a specie, the better its function as a reducing agent. Zn has a very negative reduction potential hence it a very good reducing agent. Similarly, iodine has a very positive reduction potential hence it is a good oxidizing agent.

Only a specie having a more negative reduction potential than zinc can reduce it in aqueous solution. Similarly, the reaction potential of hydrogen is less than that of iodine hence hydrogen gas can reduce iodine.