Question

write the definitions of all the 5 types of chemical reactions with examples

Answer 1

1.) Combination reaction:
When two or more simpler substances combine to form one product, the reaction is called Combination reaction. E.g.
2H2 + O2 ------------------> 2h2O
2.) Decomposition reaction:
When a substance breaks or decomposes into two or more simpler substances, on provision of energy, the reaction is called as decomposition reaction. it can be of three types- thermal decomposition(provision of energy in the form of energya), elctrolysis( on provision of electricity), photothermal(on provision of sunlight). E.g.
2AgCl------------------->2Ag + Cl2
3.) Displacement reaction
When a highly active metal displaces a lesser reactive metal from its salt solution or its  compound,then the type of reaction is called displacement reaction.E.g.
Fe + CuSO4 --------------> FeSO4 + Cu
4.)Double Displacement reaction
when during a reaction the ions of two different compounds exchange to form two different compounds the type of reaction is called as double displacement reaction.In this type of reaction precipitate is also formed. E.g.
Na2SO4 + BaCl2 ------------------> BaSO4 + 2NaCl
5.) Oxidation and Reduction.
If in a reaction following changes takes place, it is oxidation
     addition of oxygen
     removal of hydrogen
     addition of non metal 
     removal of metal
REDUCTION- OPPOSITE OF ALL POINTS MENTIONED ABOVE.
If in any reaction both reduction and oxidation occurs then the reaction is called as redox reaction.
e.g.
Cuo + H2 ----------> Cu + H2O