Question

what is addition reaction with explaination

Answer 1

A addition reaction occurs when atoms are added to a compound containing a double or triple bond. Think of an addition reaction as two different reactants combined in a large single product that contains all the elements present in the individual reactants.
the product of addition reactions contains all the atoms and elements originally present in the reactants being combined. 

Answer 2

In addition reaction, two molecules combine to create one bigger molecule.

An addition reaction is an organic reaction in which two or more molecules recombine to form a larger molecule. The reaction only occurs between chemical compounds that have multiple bonds.

Hope this helps......