How Many Types of Chemical Reactions Are There?

Ways of Classifying Chemical Reactions

Not all chemical reactions produce visible change, but bubbles, color, or temperature changes are common. It's a good idea to memorize the main types of chemical reactions.
Not all chemical reactions produce visible change, but bubbles, color, or temperature changes are common. It's a good idea to memorize the main types of chemical reactions. Trish Gant / Getty Images

Question: How Many Types of Chemical Reactions Are There?

There is more than one way to classify chemical reactions, so you may be asked to name the 4, 5, or 6 main types of chemical reactions. Here is a look at the main types of chemical reactions, with links to detailed information about the different types.

Answer: When you get right down to it, there are millions of known chemical reactions! As an organic chemist or chemical engineer, you might need to know the details about a very specific type of chemical reaction, but most reactions can be grouped into just a few categories.

The problem is determining how many categories this is! Typically, chemical reactions are grouped according to the main 4 types of reaction, 5 types of reactions, or 6 types of reactions. Here is the usual classification:

4 Main Types of Chemical Reactions

The four main types of chemical reactions are fairly clear-cut, however, there are different names for the reaction categories. It's a good idea to become familiar with the various names so that you can identify a reaction and communicate with people who may have learned it under a different name.

  1. synthesis reaction (also known as a direct combination reaction)
    In this reaction, reactants combine to form a more complex product. Often there are two or more reactants with only a single product. The general reaction takes the form:
    A + B → AB

     

  2. decomposition reaction (sometimes called an analysis reaction)
    In this kind of reaction, a molecule breaks into two or more smaller pieces. It's common to have one reactant and multiple products. The general chemical reaction is:
    AB → A + B

     

  1. single displacement reaction (also called a single replacement reaction or substitution reaction)
    In this type of chemical reaction, one reactant ion changes place with another. The general form of the reaction is:
    A + BC → B + AC

     

  2. double displacement reaction (also called a double replacement reaction or metathesis reaction)
    In this type of reaction, both cations and anions exchange places, according to the general reaction:
    AB + CD → AD + CB

    5 Main Types of Chemical Reactions

    You simply add one more category: the combustion reaction. The alternate names listed above still apply.

    1. synthesis reaction
    2. decomposition reaction
    3. single displacement reaction
    4. double displacement reaction
    5. combustion reaction
      A general form for a combustion reaction is:
      hydrocarbon + oxygen → carbon dioxide + water

    6 Main Types of Chemical Reactions

    The sixth type of chemical reaction is an acid-base reaction.

    1. synthesis reaction
    2. decomposition reaction
    3. single displacement reaction
    4. double displacement reaction
    5. combustion reaction
    6. acid-base reaction

    Other Major Categories

    Other main categories of chemical reactions include oxidation-reduction (redox) reactions, isomerization reactions, and hydrolysis reactions.

    Can a Reaction Be More Than One Type?

    As you start adding more and more types of chemical reactions, you'll notice a reaction may fit into multiple categories. For example, a reaction may be both an acid-base reaction and a double displacement reaction.