OXIDATION AND REDUCTION

 OXIDATION

During a chemical reaction, if a substance gains oxygen or loses hydrogen it is said to be oxidised. 

Eg 1:- 

when copper powder is heated in a china dish, we can observe the surface of copper powder is covered with a black colour. That black coloured substance is cupric oxide or copper (ll) oxide. Here copper gains oxygen and becomes cupric oxide.

Copper + oxygen—> cupric oxide 

2Cu + O₂—> 2CuO

Eg 2:- magnesium oxide react with hydrochloric acid to produce magnesium chloride, water and chlorine 

MnO₂ + 4HCl—> MnCl₂ + 2H₂O + Cl₂

In above reaction HCl loses hydrogen and produce Cl₂, So it’s oxidation.

REDUCTION 

During a chemical reaction, if a substance loses oxygen or gains hydrogen it undergoes reduction.

Eg:- cupric oxide + hydrogen—> Copper + water

CuO + H₂—> Cu + H₂O

Here cupric oxide (CuO) loses oxygen and becomes Cu. So CuO is reduced to Cu.

REDOX REACTION

A chemical reaction in which both oxidation and reduction taking place is known as redox reaction.

Eg:- cupric oxide + hydrogen—> Copper + water

CuO + H₂—> Cu + H₂O

Here cupric oxide (CuO) loses oxygen and becomes Cu. So CuO is reduced to Cu. While hydrogen(H₂) gains oxygen and becomes water(H₂O), so hydrogen is oxidised to water.