Science, Tech, Math › Science How Many Types of Chemical Reactions Are There? Ways of Classifying Chemical Reactions Share Flipboard Email Print 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 Science Chemistry Basics Chemical Laws Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated March 08, 2018 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. 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. 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 → ABDecomposition 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 + BSingle 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 + ACDouble 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. synthesis reactiondecomposition reactionsingle displacement reactiondouble displacement reactioncombustion reactionA general form of 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. synthesis reactiondecomposition reactionsingle displacement reactiondouble displacement reactioncombustion reactionacid-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.