Chapter 19.3

Oxidizing and Reducing Agents

Objectives:1. Relate chemical activity to oxidizing and

reducing strength.

2. Explain the concept of disproportionation.

Oxidizing and Reducing Agents• A reducing agent is a substance that has

the potential to cause another substance to be reduced.

• An oxidizing agent is a substance that has the potential to cause another substance to be oxidized.

Iron - oxidized

Copper - reduced

Iron – reducing agent

Copper – oxidizing agent

Strengths of Oxidizing and Reducing Agents

• Different substances can be compared and rated by their relative potential as reducing and oxidizing agents.

• The negative ion of a strong oxidizing agent is a weak reducing agent.

• The positive ion of a strong reducing agent is a weak oxidizing agent.

Disproportionation

• A process in which a substance acts as both an oxidizing agent and a reducing agent is called disproportionation.

• A substance that undergoes disproportionation is both self-oxidizing and self-reducing.

example: Hydrogen peroxide is both oxidized and reduced -1 -1 0

2 2 2 22H O 2H O O