CBSE Class 10 Answered

Redox reactions:

Oxidation and reduction reactions occur together. When oxidation of one substance occurs, reduction of the other substance also takes place. Such reactions are called redox reactions. In the name “redox”, the term “red”stands for reduction and “ox” stands for oxidation.

Consider the redox reaction between hydrogen sulphide and chlorine.

In the reaction between hydrogen sulphide and chlorine, the products formed are hydrogen chloride and sulphur.

H₂S + Cl₂ → 2HCl + S

Hydrogen Chlorine Hydrogen Sulphur

sulphide chloride

When an atom or a group of atoms loses electrons, oxidation takes place. In this reaction, hydrogen sulphide is oxidised to sulphur.

H₂S → S

S^-2 - 2 e^- → S

Sulphide ion Sulphur

Since, hydrogen sulphide loses electrons it is called as a reducing agent.

When an atom or a group of atoms gains electrons, reduction takes place. Chlorine is reduced to hydrogen chloride.

Cl₂ → HCl

2Cl + 2 e ^? → 2Cl ^?

Chlorine Chloride ion

Since, chlorine accepts electrons it is called as an oxidising agent.