Explanation
Let us first define the different types of reaction.
A combination reaction is one in which two reactants combine to form a single product.
[tex]2Na+O_2\rightarrow Na_2O_2[/tex]
A decomposition reaction will be one in which a reactant breaks down into two or more products.
[tex]2HCl\rightarrow H_2+Cl_2[/tex]
A simple displacement reaction will be one in which a reagent, which is in its natural state, displaces one element bound to another. As a product, we will have the previously linked element now in its free form.
[tex]Mg+MnCl_2\rightarrow Mn+MgCl_2[/tex]
In a double displacement reaction two linked elements move past each other and take each other's place.
[tex]NaF+KBr\rightarrow NaBr+KF[/tex]
