When it comes to the type of reactions, it is essential to know what a reaction is. Basically, a chemical reaction is a procedure which always converts the reactants into products. Now, the query arises what these reactants are and how they react with each other to form products. Well, the substances which are initially involved in the chemical reactions are termed as reactants and their ability to form the products depends upon the type of reactions.

Now, let’s consider the different type of reactions but always remember that neither the energy nor the matter is created or destroyed in any of these reactions. Only, there are some changes, whether the slight or huge in both the energy and the substances. And the type of reactions could be determined on the basis of these changes.

So, first of all, consider the most common type of reactions, which are combination reactions. In these reactions, two or more chemical compounds or elements combine to form a new and complex product. That’s why this type of reactions is also known as synthesis reaction. For instance, you can take the example of ammonia, which is created by the combination of two molecules of Nitrogen and three molecules of Water. This reaction could be written as follows:
            N2 + 3 H2 = 2NH3

The second most important type of reactions is Isomerisation reaction in which a chemical compound changes its structural arrangement without changing its atomic composition. After Isomerisation, it’s time to consider the analysis or chemical decomposition reaction. In this type of reactions a compound is decomposed into several small elements or compounds. For example, you can take the example of the decomposition of two water molecules in which two molecules of the hydrogen and one molecules of oxygen is released. This reaction could be shown as below:
            H2O = 2 H2 + O2

Apart from this, there is some more type of reactions, which include Single displacement and double displacement reactions. In single displacement reactions, as the name depicts, an element of the one compound is displaced by another more reactive element of the other compound. Whereas in double displacement type of reactions, two compounds exchange their bonds or ions in order to form different compounds. You can consider both of these reactions by the means of following examples:
Single displacement:    2 Na(s) + 2 HCl(aq) ( 2 NaCl (aq) + H2 (g)
Double displacement:  NaCl(aq) + AgNO3 (aq) ( NaNO2 (aq) + AgCl 2 (aq)