What do you mean by reaction....

Dear Student

Chemical reaction is defined as the process which leads to transformation of chemical substances from one form to another. In a chemical reaction the substances undergoing transformation are called reactant and the new substances that are formed are called products. 

For example A + B ―> C + D represents a chemical reaction in which reactants A and B undergo transformation to form products C and D. 

The transformation can occur by combination of more than one reactant, decomposition of a reactant and displacement of atoms or molecules in one reactant by atoms or molecules of other reactants.
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