Redox Reactions – Notes

Classical Concept
In a redox reaction oxidation and reduction occurs simultaneously.
Oxidation reactions are those reactions which include addition of oxygen or an electronegative element to a substance or removal of hydrogen or an electropositive element from a substance.
Reduction reactions are those reactions which include removal of oxygen or an electronegative element from a substance or addition of hydrogen or an electropositive element to a substance.

Electronic Concept
Loss of electrons by any species is known as oxidation.
Gain of electrons by any species is known as reduction.
In a redox reaction, the substance that denotes electrons to reduce the other substance is known as a reducing agent.
In a redox reaction, the substance that accepts electrons to oxidize other substance is known as an oxidizing agent.
The series obtained when the metals are arranged in the decreasing order of their ability to denote electrons is known as metal activity series or chemical electrochemical series.