Topic 3

 

             Oxidizing and Reducing Agents: A Brief Overview

Oxidizing agents and reducing agents are substances involved in redox reactions (reduction-oxidation reactions). These reactions involve the transfer of electrons between chemical species.

Oxidizing Agents

●     Definition: Oxidizing agents are substances that accept electrons from other substances.

●     Process: When an oxidizing agent accepts electrons, it becomes reduced.

●     Examples:

○     Oxygen (O₂)

○     Hydrogen peroxide (H₂O₂)

○     Potassium permanganate (KMnO₄)

○     Chlorine (Cl₂)

○     Nitric acid (HNO₃)

Reducing Agents

●     Definition: Reducing agents are substances that donate electrons to other substances.

●     Process: When a reducing agent donates electrons, it becomes oxidized.

●     Examples:

○     Hydrogen (H₂)

○     Carbon monoxide (CO)

○     Sodium (Na)

○     Magnesium (Mg)

○     Sulfur dioxide (SO₂)

Key Points

●     Redox Reactions: In redox reactions, both oxidation and reduction occur simultaneously.

●     Oxidation Number: The oxidation number of an atom is a measure of its electron state. An increase in oxidation number indicates oxidation, while a decrease indicates reduction.

●     Balancing Redox Equations: Redox equations must be balanced to ensure that the number of electrons lost by the reducing agent equals the number of electrons gained by the oxidizing agent.

●     Applications: Redox reactions are essential in various processes, including:

○     Corrosion

○     Combustion

○     Electrochemistry

○     Metabolism

Example of a Redox Reaction: The reaction between zinc metal and copper(II) ions is a classic redox reaction:

Zn(s) + Cu²⁺(aq) → Zn²⁺(aq) + Cu(s)

 

In this reaction, zinc metal loses two electrons (oxidation) to become Zn²⁺ ions, while Cu²⁺ ions gain two electrons (reduction) to become copper metal.