Science, Tech, Math › Science What Is the Difference Between Oxidation and Reduction? Share Flipboard Email Print Electrons are gained in oxidation and lost in reduction. GIPhotoStock / 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 Todd Helmenstine Todd Helmenstine is a science writer and illustrator who has taught physics and math at the college level. He holds bachelor's degrees in both physics and mathematics. our editorial process Todd Helmenstine Updated October 02, 2019 Oxidation and reduction are two types of chemical reactions that often work together. Oxidation and reduction reactions involve an exchange of electrons between reactants. For many students, the confusion occurs when attempting to identify which reactant was oxidized and which reactant was reduced. What is the difference between oxidation and reduction? Oxidation vs. Reduction Reduction and oxidation occur simultaneously in a type of chemical reaction called a reduction-oxidation or redox reaction.The oxidized species loses electrons, while the reduced species gains electrons.Despite the name, oxygen need not be present in an oxidation reaction. Oxidation vs Reduction Oxidation occurs when a reactant loses electrons during the reaction. Reduction occurs when a reactant gains electrons during the reaction. This often occurs when metals are reacted with acid. Oxidation and Reduction Examples Consider the reaction between zinc metal and hydrochloric acid. Zn(s) + 2 HCl(aq) → ZnCl2(aq) + H2(g) If this reaction where broken down to the ion level: Zn(s) + 2 H+(aq) + 2 Cl-(aq) → Zn2+(aq) + 2 Cl-(aq) + 2 H2(g) First, look at what happens to the zinc atoms. Initially, we have a neutral zinc atom. As the reaction progresses, the zinc atom loses two electrons to become a Zn2+ ion. Zn(s) → Zn2+(aq) + 2 e- The zinc was oxidized into Zn2+ ions. This reaction is an oxidation reaction. The second part of this reaction involves the hydrogen ions. The hydrogen ions are gaining electrons and bonding together to form dihydrogen gas. 2 H+ + 2 e- → H2(g) The hydrogen ions each gained an electron to form the neutrally charged hydrogen gas. The hydrogen ions are said to be reduced and the reaction is a reduction reaction. Since both processes are going on at the same time, the initial reaction is called an oxidation-reduction reaction. This type of reaction is also called a redox reaction (REDuction/OXidation). How to Remember Oxidation and Reduction You could just memorize oxidation: lose electrons-reduction: gain electrons, but there are other ways. There are two mnemonics to remember which reaction is oxidation and which reaction is reductions. The First One is OIL RIG Oxidation Involves Loss of electronsReduction Involves Gain of electrons. The Second Is 'LEO the Lion Says GER' Lose Electrons in OxidationGain Electrons in Reduction. Oxidation and reduction reactions are common when working with acids and bases and other electrochemical processes. Use these two mnemonics to help keep in mind which process is the oxidation and which is the reduction reaction.