8 types of chemical reactions with examples

The main types of chemical reactions are:

Acid-base reactions
Oxidation-reduction reactions
combustion reactions
displacement reactions
Double displacement reactions
Acid-metal reactions
combination reactions
decomposition reactions

A chemical reaction is the process of arranging atoms between substances to form new compounds with different properties. That is, when compounds or elements react, they are transformed into one or more different substances.

For example, when paper is burned, the oxygen in the air and the cellulose in the paper react, turning into carbon dioxide and water vapor.

The substances that react are called reactants and the substances that are generated are called products. The chemical reaction is represented by a chemical equation, where the reactants are placed to the left of an arrow followed by the products to the right, like this:

Reactants→Products

A nuclear reaction is not a chemical reaction, since the transformation of atoms into another type of atom occurs. For example, in the fission of uranium, krypton and barium are formed, while mass is lost as energy. Neither are chemical reactions the dissolution of a substance in water or the ionization of a compound, as well as the change of state of a material.

instagram story viewer

Here are the main types of chemical reactions with examples.

1. Acid-base reactions

Also called neutralization reactions, the reaction of an acid with a base occurs. The acid contributes H ions.⁺ and the base contributes OH ions^- to form water H₂Or, at the same time that a salt is formed.

For example, when hydrochloric acid HCl reacts with sodium hydroxide NaOH, the products are water H₂O and the sodium chloride salt NaCl:

bold HCl bold space bold plus bold space bold NaOH bold right arrow bold NaCl bold space bold plus bold space bold H subscript bold 2 bold O

You may also be interested in seeing Acids and bases.

2. Oxidation-reduction reactions

They are a type of chemical reaction where reactants gain or lose electrons to each other. When they gain electrons they are reduced, when they give up electrons they are oxidized. Oxidation and reduction reactions are simultaneous.

For example, for iron extraction in mines, iron oxide III F_and2O₃ it is reduced by the action of carbon monoxide CO which is oxidized. The products are iron in its element form Fe and carbon dioxide CO₂:

style size 16px bold Fe bold subscript 2 bold OR bold subscript 3 bold plus bold space bold 3 bold CO bold space bold right arrow bold 2 bold Fe bold space bold plus bold space bold 3 bold CO subscript bold 2 end style

You may also be interested in seeing Oxidation and reduction.

3. combustion reactions

In combustion reactions, oxygen combines with organic compounds, made up of carbon, hydrogen, and oxygen. The end product is carbon dioxide and water.

An example of a combustion reaction is that which occurs when methane CH is burned₄ or cooking gas:

bold CH subscript bold 4 open parenthesis bold g close parenthesis end subscript bold plus bold 2 bold O subscript bold 2 open parenthesis bold g close parenthesis end subscript bold right arrow bold CO subscript bold 2 open parenthesis bold g close parenthesis end subscript bold plus bold 2 bold H subscript bold 2 bold O subscript open parenthesis bold g close parenthesis end subscript

You may also be interested in seeingOrganic and inorganic compounds.

4. displacement reactions

In this type of reaction, one element replaces another in a compound. Such is the case of the reaction between sodium Na and zinc iodide ZnI₂, where sodium displaces zinc to form sodium iodide NaI:

style size 16px bold 2 bold Na bold space bold plus bold space bold ZnI subscript bold 2 bold right arrow bold 2 bold NaI bold space bold plus bold space bold Zn end style

5. Double displacement reactions

This reaction occurs in solution when the reactants become ionized such that ion exchange occurs. If the combination produces a compound that precipitates by forming an insoluble salt, we have a precipitation reaction.

For example, when reacting barium nitrate salts Ba (NO₃)₂ and potassium sulfate K₂SW₄, the ions are exchanged to produce potassium nitrate KNO₃ and barium sulfate BaSO₄ which is insoluble in water and precipitates:

bold Ba bold left parenthesis bold NO subscript bold 3 bold right parenthesis subscript bold 2 bold space bold plus space bold K subscript bold 2 bold SO subscript bold 4 bold right arrow bold 2 bold KNO subscript bold 3 bold space bold plus space bold BSO subscript bold 4

6. Acid-metal reactions

An acid such as hydrochloric acid HCl and a metal can react to form a salt and hydrogen gas H₂:

bold 2 bold HCl bold space bold plus bold space bold 2 bold Na bold arrow right bold 2 bold NaCl bold space bold plus bold space bold H subscript bold 2

7. combination reactions

Elements or compounds combine to form a different product. For example, sulfur dioxide SO₂ combines with oxygen O₂ to form sulfur trioxide SO₃:

bold 2 bold SW subscript bold 2 bold space bold plus bold space bold OR subscript bold 2 bold right arrow bold 2 bold SW subscript bold 3

8. decomposition reactions

A simple compound gives rise to two or more products. An example of decomposition is the process of electrolysis, that is, when an electric current passes through water, it decomposes into hydrogen gas H₂ and oxygen:

bold 2 bold H subscript bold 2 bold O bold right arrow with bold electricity above bold 2 bold H subscript bold 2 bold plus bold space bold O subscript bold 2

References

Ahtee, M., Varjola, I. (2007) Students' understanding of chemical reaction. International Journal of ScienceEducation. 20: 305-316. DOI: 10.1080/0950069980200304

Commons, C., Commons, P (coordinators) (2020). Heinemann Chemistry 1, 5th ed. PearsonAustralia. Melbourne.

Rosenberg JL, Epstein LM, Krieger PJ. (2007) Schaum's outlines College Chemistry 9th ed. McGraw-Hill. Toronto.