Oxidation-Reduction Reactions

Oxidation-Reduction Reactions

(1) Oxidation: Oxidation is a process which involves; addition of oxygen, removal of hydrogen, addition of non-metal, removal of metal, Increase in +ve valency, loss of electrons and increase in oxidation number.

(i) Addition of oxygen: 2Mg + O2 2MgO

(ii) Removal of hydrogen: H2S+Cl22HCl + S

(iii) Addition of Non-metal: Fe + S FeS

(iv) Removal of metal: 2KI+H2O22KOH+I2

(v) Increase in +ve valency :

(vi) Loss of electrons (also known as de-electronation)


Loss of electrons

(a) (Formation of proton)

(b) (De-electronation of )

(c) (De-electronation of iron)

(vii)Increase in oxidation number

(a) (From 0 to +2)

(b) (From +2 to +3)

(c) (From –1 to 0)

(2) Reduction: Reduction is just reverse of oxidation. Reduction is a process which involves; removal of oxygen, addition of hydrogen, removal of non-metal, addition of metal, decrease in +ve valency, gain of electrons and decrease in oxidation number.

(i) Removal of oxygen:

(ii) Addition of hydrogen:

(iii) Removal of non-metal

(iv) Addition of metal:

(v) Decrease in +ve valency


(a) (+ve valency decreases)

(b) (–ve valency increases)

(vi) Gain of electrons (also known as electronation)


Gain of electrons

(a) (Electronation of )

(b) (Electronation of )

(c) (Electronation of )

(vii) Decrease in oxidation number

(a) (From +2 to 0)

(b) (From +3 to +2)

(c) (From 0 to –1)

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