Question

Rank these species by their ability to act as an oxidizing agent (20)

Answer 1

Al³⁺_(aq) + 3e^- ? Al_(s)           -1.66 V Strong reducing agent

Zn²⁺_(aq) + 2e^- ? Zn_(s) -0.76 V

Pb²⁺_(aq)  + 2e^- ? Pb_(s) -0.13 V

Au³⁺_(aq) + 3e^- ? Au_(s)       +1.50 V Strong oxidizing agent

Notice the 0.0 V potential assigned to hydrogen ion. A positive reduction potential means that the oxidizing agent (such as Au3+) has a greater tendency to be reduced than the hydrogen ion, and is therefore a stronger oxidizing agent. A negative reduction potential for an oxidizing agent (such as Al3+, Zn2+) indicates that the hydrogen ion is more readily reduced than that substance.

Answer 2

au>pb>zn>al

Answer 3

Zn2+ > Pb 2+ > Al 3+ > Au 3+