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The chapter also details how to construct predominance/existence regions and how to overlay the E-pH stability diagram of water to assess possible redox reactions, including hydrogen and oxygen formation.",{"@graph":14,"@context":72},[15,34,55],{"@type":16,"itemListElement":17},"BreadcrumbList",[18,23,27,31],{"item":19,"name":20,"@type":21,"position":22},"https://docshare.wps.com","Home","ListItem",1,{"item":24,"name":25,"@type":21,"position":26},"https://docshare.wps.com/document/","Document",2,{"item":28,"name":29,"@type":21,"position":30},"https://docshare.wps.com/document/research-report/","Research & 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diagrams?","Question",{"text":62,"@type":63},"Pourbaix diagrams show the pH–potential regions where different chemical forms of an element (ions, complexes, precipitates, metals) are present or dominant, and where they are thermodynamically stable.","Answer",{"name":65,"@type":60,"acceptedAnswer":66},"How does the Nernst equation relate to Pourbaix diagrams?",{"text":67,"@type":63},"The Nernst equation describes the oxidation–reduction boundary lines on E-pH diagrams, linking redox equilibria to changes in acidity (pH) and the medium.",{"name":69,"@type":60,"acceptedAnswer":70},"How can the E-pH stability diagram of water be used in redox predictions?",{"text":71,"@type":63},"By overlaying water’s potential–pH diagram onto the studied diagram, one can determine whether redox reactions with water are thermodynamically possible and whether water will oxidize to oxygen, reduce to hydrogen, or remain stable between boundary 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exception of the noblest (gold), are not stable intheir metallic state. Instead, they exist in oxidized form in ores. Consequently, metals have anatural tendency to oxidation, either through passivation or corrosion. The thermodynamicstability domains of these various forms can be represented on pH potential diagrams, or Pourbaixdiagrams. These diagrams indicate the regions where various forms (ions, complexes, precipitates,metals) of the chemical element are present or dominant, as well as their regions of stability. TheNernst equation forms the basis of this concept, enabling us to understand how the change in theacidity of the medium might affect the redox properties of the pair. The water's potential-pHdiagram is included in this graphic determine if redox reactions are possible with the water.Typically, redox reactions with water are often very slow. As a result, it is possible to prepareaqueous solutions of oxidant or reductant.  \nThere are three main areas in Pourbaix diagram :  \n- Immunity domain: The metal is thermodynamically unassailable stable under the actionof the surrounding environment. In practice, this is observed for noble metals, on other metals itis necessary to acton the potential to bring them to this area, this isthe basis of cathodic protection.  \n- Passivation domain: It refers to a situation when the corrosion of a metal leads to theformation of a stable corrosion product that can act as a protective barrier.  \n- Corrosion domain: Where acidic or basic corrosion occurs, and the metal ions orcomplexes are stable.  \nDomains of predominance (DP) and domains of existence (DE)  \nPrior to commencing the construction of a Bourbet diagram, it is imperative to determinethe areas of predominance and presence of the species being investigated. Hence, the presence andcontrol of various species are determined by the horizontal, vertical, and diagonal lines. Byunderstanding the systemic potential, we may accurately identify the regions of stability for theelement and its compound. However, it is essential for us to be aware of the redox pairs and theoxidation number for each element.  \nPourbaix diagrams necessitate the use of highly accurate rules.  \nA Pourbaix diagram pertains to a certain chemical element. Determine the specific speciesinvolved and establish the oxidation number of the element in each of them.  \nThe chemical species are positioned on the diagram based on their increasing oxidationnumber along the axis of potentials.  \nChemical species that have the same oxidation number will be separated by verticalboundaries.  \nTo simplify matters, we make the assumption that the solutions and gases involved areperfect. Consequently, activities will be assimilated into concentrations (for dissolved species) orpartial pressures (for gaseous species) . The activitie of solid species will be equal to 1.  \nIn order to apply Nernst's law or analyze acid-base balances, it is essential to haveknowledge of the concentrations of specific chemical species.  \nThe boundaries of oxidation-reduction equilibria can be described by Nernst's law, whichprovides the equation for these boundaries, and these boundaries can be either horizontal oroblique. In order to apply Nernst's law or analyze acid-base balances, it is essential to haveknowledge of the concentrations of specific chemical species.  \nE-pH Diagram ofWater  \nGiven that water is most common solvent, it is imperative to assess its thermodynamicstability by an examination of its potential acidity-potential diagram. We will systematicallyoverlay the potential-pH diagram of water onto the diagram we are analyzing in order to predictthe behavior of the species depicted in the diagram when exposed to water. The H2O molecule isamphiprotic, meaning it can function asboth a reference or as an oxidant.  \n􀜪2 O ↔ 􀜱􀜪 − + 􀜪 +[􀜪3􀜱 + ] . [􀜱􀜪 − ] = 10 −14 = 􀜭􀝁􀝌􀜪 = −􀝈","cbCairTQeWeqU0jl","https://ap.wps.com/l/cbCairTQeWeqU0jl","pdf",1336954,12,"English","# Phase diagrams, Potential-pH diagram, Applications\n## 1. Fe E-pH (Pourbaix) Diagram","[{\"question\":\"What is the purpose of Pourbaix (E-pH) diagrams?\",\"answer\":\"Pourbaix diagrams show the pH–potential regions where different chemical forms of an element (ions, complexes, precipitates, metals) are present or dominant, and where they are thermodynamically stable.\"},{\"question\":\"How does the Nernst equation relate to Pourbaix diagrams?\",\"answer\":\"The Nernst equation describes the oxidation–reduction boundary lines on E-pH diagrams, linking redox equilibria to changes in acidity (pH) and the medium.\"},{\"question\":\"How can the E-pH stability diagram of water be used in redox predictions?\",\"answer\":\"By overlaying water’s potential–pH diagram onto the studied diagram, one can determine whether redox reactions with water are thermodynamically possible and whether water will oxidize to oxygen, reduce to hydrogen, or remain stable between boundary lines.\"}]","Chapter 2 - Phase diagrams, Potential-pH diagram, Applications | PDF"]