Question

Rank these species by their ability to act as an oxidizing agent.

Fe2+, Pb2+, Au3+, Mg2+

Answer 1

Solution: An oxidizing agent is an agent which oxidizes its counterpart and in the process reduces itself. The ability of an ion to act as a strong oxidizing agent can be looked over by looking at the standard reduction potential values.

If the standard reduction potential of an ion is high (positive) then the ion will have a strong reducing tendency and will be a strong oxidizing agent, and if it shows a low (negative) value , then the ion will show a more oxidizing tendency than reducing and the oxidizing agent will be weak.

Fe²⁺ / Fe = -0.44 V

Pb²⁺ / Pb = -0.13 V

Au³⁺ / Au = +1.50 V

Mg²⁺ / Mg = -2.37 V

From the above data, we conclude these species based on increasing strength of oxidizing agent:

Mg²⁺ < Fe²⁺ < Pb²⁺ < Au³⁺