NCERT Chapter Summary: Redox Reactions

Class 11 Chemistry

Redox reactions form an important class of reactions in which oxidation and reduction occur simultaneously.

Oxidation is defined as the addition of oxygen or electronegative element to a substance or removal of hydrogen or electropositive element from a substance.

Reduction is defined as the removal of oxygen or electronegative element from a substance or addition of hydrogen or electropositive element to a substance.

Oxidation: Loss of electron(s) by any species.

Reduction: Gain of electron(s) by any species.

Oxidising agent: Acceptor of electron(s).

Reducing agent: Donor of electron(s).

Oxidation number denotes the oxidation state of an element in a compound ascertained according to a set of rules formulated on the basis that electron pair in a covalent bond belongs entirely to more electronegative element.

Redox reactions are classified into four categories: combination, decomposition, displacement and disproportionation reactions. In a disproportionation reaction an element in one oxidation state is simultaneously oxidised and reduced.

The redox reactions find wide applications in the study of electrode processes and cells.