REDOX REACTION

Oxidation and reduction always take place simultaneously therefore the reaction is often called a redox reaction.

In the chemical reaction, there are 3 types of basic reaction that involved in the oxidation and reduction.

Displacement of reaction is a type of chemical reaction, where one element replaces another element in a compound. In that reaction, more reactive element displacing a less reactive element from its compound, resulting in the formation of a new compound and the release of the displaced element.

Example of the reaction : Cl_2(g) + KI_(aq) → KCl_(aq) + I_2(g)

_{Ionic Equation is a chemical equation that shows the ion involved in aqueous solution during the reaction. the ion that do not taking part in any chemical reaction are called spectator ions and must be cross out in the reaction}

_{Example of the reaction :}Zn_(s) + Cu²⁺_(aq) +~~SO₄^2-_(aq)~~ → Zn²⁺_(aq)+ ~~SO₄^2-_(aq)~~ + Cu_(s)

Half Equation is chemical reaction involving the losing electrons ad gaining electrons

Example : (1) Losing electrons : Mg → Mg²⁺ + 2e^-

^{(2) Gaining electrons :}O +2e →O^2-

Oxidation and reduction can be classified become 4 term :

Based on Oxygen

Oxidation : substance gaining oxygen

Example : Reaction between hydrogen and oxygen to form water

Based on the reaction the hydrogen has gained oxygen and has been oxidized to water

Reduction : Substance lost of oxygen

Example : Reaction between Iron (III) oxide and Carbon monoxide to form Iron and Carbon dioxide

Based on the reaction the Iron (III) oxide has lost of oxygen and has been reduced to iron

Based on Hydrogen

Oxidation : substance remove hydrogen

Example : Reaction between Hydrogen Sulfide and chlorine to form Hydrogen Chloride and Sulfur

Based on the reaction the Hydrogen Sulfide has lost of hydrogen to causes the Hydrogen sulfide oxidized to be sulfur.

Reduction : substance adding hydrogen

Example : Reaction between Hydrogen and Chlorine to form hydrogen chloride

Based on the reaction the Chlorine has gained of hydrogen and has been reduced to form hydrogen chloride.

Based on Electrons

Oxidation : substance is losing electron

Example : Reaction magnesium and chlorine to form Magnesium Chloride

Based on the reaction the Magnesium has lost of electron and has been oxidized to form Magnesium chloride. Electron have been transfer during the reaction

Rx : Mg → Mg²⁺ + 2e-

Reduction : substance is gaining electron

Example : Reaction between the Iron (III) chloride and Hydrogen Sulfide to forming Iron (II) chloride, Hydrogen chloride and Sulfur

Based on the reaction the Iron (III) chloride has gained of electron and has been reduced into Iron (II) chloride.

Rx : Fe³⁺+ e^- → Fe²⁺

Based on oxidation state number

Oxidation : substance increasing number oxidation states

Example : Reaction between Zinc and Copper Sulfate to forming the Copper and Zinc Sulfate

Rx : Zn_(s) + CuSO_{4 (aq)} → ZnSO_{4 (aq)} + Cu_(s)

Zinc atom (oxidation state = 0) its because forming the zinc ions Zn²⁺(oxidation state = +2). the oxidation state of zinc has increased from (0 to +2 ). We say that Zinc is oxidized into Zinc ions

Reduction : substance decreasing number oxidation states

Still use in the same of reaction.

Rx : Zn_(s) + CuSO_{4 (aq)} → ZnSO_{4 (aq)} + Cu_(s)

Copper ions (Oxidation state = +2) because at the end of reaction the copper sulfate are replace by Zinc its causes the reaction becomes Copper atom (oxidation state = 0). The reduction of Copper has decreased from (+2 to 0). We say that the copper is reduced

THE RULES OF OXIDATION STATES NUMBER

1. The oxidation state for free element are zero

Example : Cu = 0, Fe = 0 , Na = 0

2. The oxidation of the simple ions is the same as the charge of the ion

Example : Zn²⁺ = 2

3. The oxidation state of the atom present in the formula of compound add up to zero

Example : CaCO₃ = +2+4-6 = 0

4. The total of the oxidation state of the atom in a poly atomic ion is equal to the charge of ion

Example : SO₄^- = +6-8 = -2