On chemical reaction
And its types
Submitted by Submitted to
Samar kansal Mr. Manish sir
Roll no.38 (subject in charge)
What is a chemical reaction
Types of chemical reactions
Double displacement reactions
A chemical process(or change ) in which certain
substances react together to form some new
substances having different properties is called a
The substances which take part in a
chemical reaction are called reactants and the
substances formed in a chemical reaction are called
In a chemical reaction, the amount of
reactants decreases whereas that of products
increases with time, until the reaction is over.
What is a chemical
We have studied that the chemical involves simply the
exchange of partners in the reactants to form products.
Neither the atoms disappear from the reaction mixture nor
new atoms appear in the same. In fact, the chemical reaction
bonds present in the reacting species break and new bonds in
the product species are formed.
Chemical reaction are classified into 5 types. They are:-
1.Combination reactions 2.decomposition reaction
3displacement reactions 4.double displacement reactions
5. Oxidation and reduction reactions
Types of chemical reactions
Combination reactions may be defined as :
The reaction in which two or more substances combine to
form a single substance under suitable conditions.
In these reactions, the combination may be takes place
Two or more elements
Two or more compounds
Elements and compounds
For example:- combustion of coal
C(s) + O2 ----> CO2
Decomposition reactions may be defined as :
the reactions in which a single substance splits into
two or more simple substances under suitable
The decomposition reactions are mostly endothermic in
nature. Energy in the form of heat, light or electricity is
generally absorbed in these reactions. It causes the
cleavage or breaking of the bonds in the reacting
substances which decompose to give the products.
For example :- Decomposition of potassium chlorate
2KClO3 ---- 2KCl + 3O2
Displacement reactions may be defined as :
the chemical reactions in which one element takes the
position or place of another element present in a compound.
The displacement reactions are very common in the metals.
Normally, a more reactive metal displaces a less reactive
metal present as its salt dissolved in water. The reaction is
often known as metal displacement reaction.
For example :- zinc displaces iron from the aqueous solutions
of ferrous sulphate
Zn + FeSO4 ----- ZnSO4 + Fe
Double displacement reactions may be defined as :
the chemical reaction in which one component each of
both the reacting molecules get exchanged to form the
products. This means that double displacement has
taken place .
For example :- A white precipitate of barium sulphate is
immediately formed as a result of double displacement
BaCl2 + Na2SO4 ------ BaSO4 + 2NaCl