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Welcome to the ChemWiki > Analytical Chemistry > Electrochemistry > Redox Chemistry > Oxidizing and Reducing Agents
Oxidizing and Reducing AgentsFrom $1Table of contents
IntroductionOxidizing and reducing agents are key terms used in describing the reactants in redox reactions. To review, a redox reaction involves transferring electrons between reactants to help form products. In this module, we will look at what defines an oxidizing and reducing agent, how to determine an oxidizing and reducing agent in a chemical reaction, and its importance through real world applications. Contents
Oxidizing AgentsAn oxidizing agent, or oxidant, gains electrons from a reducing agent in a chemical reaction. Also known as the electron acceptor, the oxidizing agent is normally in one of its higher possible oxidation states because it will gain electrons and be reduced. Examples of oxidizing agents include halogens, potassium nitrate, and nitric acid. Reducing AgentsA reducing agent, or reductant, loses electrons in a chemical reaction to the oxidizing agent. A reducing agent typically is in one of its lower possible oxidation states, and is known as the electron donor. A reducing agent is oxidized because it loses electrons in the redox reaction. Examples of reducing agents include the earth metals, formic acid, and sulfite compounds.
Helpful MnemonicsRemember that a reducing agent will oxidize the other substance and gain electrons; therefore, its oxidation state will increase. An oxidizing agent, reduces the other substances causing it to lose electrons. To help eliminate confusion, here are a few mnemonic devices to help you remember how to determine oxidizing and reducing agents.
Cl2 (aq) + 2Br- (aq) --> 2Cl- (aq) + Br2 (aq)
Oxidation: 2Br- (aq) --> Br2 (aq)
-1 0
Reduction: Cl2 (aq) --> 2Cl- (aq)
0 -1
The Br- gives up electrons, it is being oxidized from Br- to Br2, thus is a reducing agent.
The Cl2 gains electrons, it is being reduced from Cl2to2Cl-, thus is an oxidizing agent.
ApplicationsOxidizing and reducing agents are important in industrial applications. They are used in processes such as purifying water, bleaching fabrics and storing energy (such as in batteries and gasoline). Oxidizing and reducing agents are especially crucial in biological processes such as metabolism and photosynthesis. For example, organisms utilize electron acceptors such as NAD+ to harvest energy from redox reactions as in the hydrolysis of glucose: C6H12O6 + 2ADP + 2P + 2NAD+ --> 2 CH3COCO2H + 2 ATP + 2 NADH All combustion reactions are also examples of redox reactions. A combustion reaction occurs when a substance reacts with oxygen to create heat. One example is the combustion of octane, the principle component of gasoline: 2C8H18 (l) + 25O2 (g) 16CO2 (g) + 18H2O (g) Combustion reactions are a major source of energy for modern industry. Summary
By looking at each element's oxidation state on the left side in comparison to the right, one can determine it it is being reduced or oxidized. Therefore, one can conclude what are the oxidizing and reducing agents of the reaction. QuizNow that you know about oxidizing and reducing agents, test yourself with some of these problems. 1) Determine the oxidizing and reducing agent of the following chemical equation for aerobic respiration. C6H12O6 (s) + 6 O2 (g) --> 6 CO2 (g) + 6 H2O (l) 2) Is A the oxidizing or reducing agent? Is B the oxidizing or reducing agent? Which one is reduced and which one is oxidized?
3) In a redox reaction, there must be A) an oxidizing agent and no reducing agent B) a reducing agent and no oxidizing agent C) a reducing agent and an oxidizing agent D) no reducing or oxidizing agent 4) Which of the following is most likely to be a strong oxidizing agent? Which of the following is most likely to be a strong reducing agent? NO3-, NO, N2H4, NH3 Answers1. The oxidizing agent is oxygen. The reducing agent is glucose. The oxygen is being reduced, so it is an oxidizing agent. The glucose is being oxidized, so it is a reducing agent.
2. When A loses electron, it is being oxidized, thus is a reducing agent. 3. C. In a redox reaction, there is always an oxidizing and reducing agent. When B gains electron, it is being reduced, thus is an oxidizing agent.
A is oxidized. B is reduced.
4. NO3- will most likely to be a strong oxidizing agent. NH3 is most likely to be a strong reducing agent. You determine the likelihood for oxidation or reduction by comparing the oxidation numbers of nitrogen. Since NO3- has the highest oxidation number of +5, compared to the other molecules, it will most likely be the oxidizing agent. Since NH3 has an oxidation state of -3, it has the lowest oxidation state and will most likely be the reducing agent. References
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Files (0) Images (5)Viewing 1 - 5 of 5 images | View All     This chemical hazard sign is used by the European Union to signify the presence of strong oxidizing agents. oxidizing... Actions Comments (3) |
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