A combination reaction is one in which two or more reactants combine to form a single product.

Examples :

Combustion of coal and reaction of calcium oxide with water

Decomposition reactions are those in which a substance splits into two or more simpler substances.

Examples:

The thermal decomposition of calcium carbonate,

 Electrolysis of water

photolysis of silver chloride

2AgCl --------> 2Ag +Cl2

Single displacement reaction is the one in which one element substitutes or displaces another element in a compound to give new compound.

Example:

The reaction of magnesium with copper chloride

Reaction in which hydrogen ions of an acid react with hydroxide ions of a base to form water is an neutralization reaction.

Example :

The reaction of hydrochloric acid with sodium hydroxide.

A double displacement reaction involves exchange of ions between the reactants.

Example:

The reaction of magnesium oxide with calcium sulphide.

Combustion reaction is the burning of a substance in the presence of oxygen, resulting in the release of energy.

Example:

Combustion of ethylene gas.

Oxidation reaction involves the addition of oxygen or the removal of hydrogen from a substance. Rusting and rancidity are two examples of oxidation reaction.

· Coating iron articles with enamel, paint or red lead oxide prevents rust.

· Addition of an anti-oxidant such as butylated hydroxy anisole (BHA) and butylated hydroxy toluene (BHT)

Packing food in nitrogen gas prevents oxidation of food.

Reduction reaction involves addition of hydrogen or removal of oxygen from a substance. Photosynthesis is a reduction reaction.

Oxidation and reduction reactions occurring together are known as redox reactions.

Chemical reactions in which energy is released are known as exothermic reactions and those which involve absorption of energy are known as endothermic reactions.