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