Chemistry
Introduction to Acids and Bases
"Introduction to Acids and Bases" is a fundamental concept in chemistry that explores the properties and behavior of acidic and basic substances. Acids are characterized by their ability to donate protons, while bases can accept protons. Understanding the behavior of acids and bases is crucial in various chemical reactions and has wide-ranging applications in fields such as medicine, industry, and environmental science.
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12 Key excerpts on "Introduction to Acids and Bases"
eBook - PDF- Young, William Vining, Roberta Day, Beatrice Botch(Authors)
- 2017(Publication Date)
- Cengage Learning EMEA(Publisher)
AlbertSmirnov/iStockphoto.com 17 Acids and Bases Unit Outline 17.1 Introduction to Acids and Bases 17.2 Water and the pH Scale 17.3 Acid and Base Strength 17.4 Estimating the pH of Acid and Base Solutions 17.5 Acid–Base Properties of Salts 17.6 Molecular Structure and Control of Acid–Base Strength In This Unit… We now continue our discussion of chemical equilibria, applying the concepts and techniques developed in Chemical Equilibrium (Unit 16) to the chemistry of acids and bases. In Advanced Acid–Base Equilibria (Unit 18) and Precipitation and Lewis Acid–Base Equilibria (Unit 19) we will continue to study chemical equilibria as it applies to acid–base reactions, buffers, and the chemistry of sparingly soluble compounds. Vasilyev/Shutterstock.com Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-300 Unit 17 Acids and Bases 528 17.1 Introduction to Acids and Bases 17.1a Acid and Base Definitions We begin our study of acids and bases with the acid and base definitions we introduced in Chemical Reactions and Solution Stoichiometry (Unit 9), the Arrhenius definitions. Arrhenius acid : A substance containing hydrogen that, when dissolved in water, increases the concentration of H 1 ions. Arrhenius base : A substance containing the hydroxide group that, when dissolved in water, increases the concentration of OH 2 ions. The Brønsted–Lowry definition is a broader description of the nature of acids and bases. Brønsted–Lowry acid : A substance that can donate a proton ( H 1 ion). Brønsted–Lowry base : A substance that can accept a proton ( H 1 ion). This definition allows us to define a larger number of compounds as acids or bases and to describe acid–base reactions that take place in solvents other than water (such as ethanol or benzene). Ammonia, NH 3 , for example, is not an Arrhenius base (its formula does not contain a hydroxide group).
eBook - ePubInorganic Chemistry for Geochemistry and Environmental Sciences
Fundamentals and Applications
- George W. Luther, III(Authors)
- 2016(Publication Date)
- Wiley(Publisher)
Chapter 7 Acids and Bases 7.1 Introduction Acids and bases have been known since before Roman times, for their ability to transform a chemical substance into other chemical forms. For example, sulfuric acid (, oil of vitriol; vitriolic acid) could be produced by the aqueous oxidation of pyrite, which is a common mineral used for many purposes [1]. dehydrates sugar as well as metal hydrates with sometimes dramatic color changes, and also dissolves metals via redox reactions. It is normally the chemical that is produced and sold in greatest quantity in the world each year. The first base was called lye, which was obtained by leaching ashes with water producing potassium hydroxide solution. Lye is a common name for bases, which are used in a variety of purposes including wood degradation into paper or fibers and soap production. 7.2 Arrhenius and Bronsted–Lowry Definitions Common acids such as hydrochloric acid (HCl) and nitric acid were not formally prepared until about the 16th century, so formal definitions of acids and bases similar to bonding theories are relatively new. In 1884, Svante Arrhenius defined an acid as a chemical species that when dissolved in water produced the hydrogen ion,. Although useful, the definition is limited as it does not encompass a large variety of reactions and only considers water as solvent. In 1923, Brønsted and Lowry defined an acid and base reaction as one that involves a hydrogen ion transfer between two reactants. The acid is the hydrogen ion donor (the Brønsted acid) and the base is the hydrogen ion acceptor (the Brønsted base). This definition applies to all solvents and the gas phase. For example, the reaction between HCl and can occur in water as solvent or in the gas phase (an atmospheric reaction) and results in complete transfer to form the hydronium ion,
eBook - PDF- Ageetha Vanamudan(Author)
- 2023(Publication Date)
- Delve Publishing(Publisher)
In this part, we’ll take a short look at each of Introduction to Molecular Science 222 them. Acids and bases can be described using one of the three principles listed below: In acidic solutions, there are two types of H + ions: those produced by acid and those produced by an alkaline solution. According to Bronsted and Lowry, an acid is a proton donor, and a base is an acceptor. For acids and bases, there exist “electron acceptors” and “electron donors,” as described by Lewis. 13.5.2 The Theory of Acids and Bases by Arrhenius According to the Arrhenius hypothesis, the H + ion is generated when acid is dissolved in water. The solution’s H + ion concentration increases. When the base is dissolved in water, it ionizes the OH - ion. As a result, the solution contains a lot of OH - ions. Arrhenius acid can be used to enhance the concentration of protons or H + ions in an aqueous solution (Kharat et al., 2017). Figure 13.6: Nitric acid in a chemical bottle. Source: https://media.istockphoto.com/photos/nitric-acid-in-glass-chemical- in-the-laboratory-picture-id1350071266?k=20&m=1350071266&s=612x612 &w=0&h=pqe5b9pVKlFszNzjoPUGXnIXMeIMCUK_qzXKRcnPq5k= 13.5.3 Arrhenius Acids Svante Arrhenius, a Swedish scientist, proposed the Arrhenius theory of acids and bases in 1884. According to his concept, acids and bases should be categorized based on the type of ions they produce when dissolved in water (O’Gorman et al., 2012). For example, a hydrochloric acid solution in water. To summarize, HCl degrades into H + and Cl – . The production of hydronium ions raises the concentration of H + ions. Acids and Bases 223 H+ (aq) + aqueous HCl (aq) In the lab, HCl (aq) + H 2 O (l) = H 3 O+ (aq) + Cl - (aq) 13.5.4 Arrhenius base To increase the concentration of water-soluble hydroxide ions in a solution, substances such as an Arrhenius base are utilized. The material must be both water-soluble and capable of dissociating into sodium and hydroxide ions to be classified as an Arrhenius base.
eBook - ePub- Jeffrey Gaffney, Nancy Marley(Authors)
- 2017(Publication Date)
- Elsevier(Publisher)
Chapter 5Acids and Bases
Abstract
This chapter explains the differences between the Brønsted-Lowry and Lewis definitions of acids and bases and gives examples of each. Since chemical reactions involving Lewis acids and bases are covered in more detail in Chapter 10, most of the chapter is dedicated to the applications of the Brønsted-Lowry concepts. This includes the strength of acids and their conjugate bases, the behavior of acids and bases in aqueous solution, the autoionization of water, and the acid ionization constants. The “p” functions, including pH, pOH, pK a , pK b , and pK w , are discussed. The function and uses of buffer solutions are explained along with their design using the Henderson-Hasselbalch equation. Titration procedures are discussed and their relevance to industrial situations is stressed.Keywords
Brønsted-Lowry; Lewis acid; Conjugate pairs; Ionization constant; Amphoteric; Coordinate-covalent bond; Coordination complex; Buffer solution; Henderson-Hasselbalch; TitrationOutline5.1Defining Acids and Bases5.2Acids and Bases in Aqueous Solution5.3The pH Scale5.4Other “p” Functions5.5Buffer Solutions5.6Important Terms Study QuestionsThe TitrationProblems5.1 Defining Acids and Bases
The first modern attempt at defining acids and bases was by a Swedish chemist named Svante Arrhenius in 1887. Arrhenius defined an acid as a material that releases hydrogen ions (H+ ) when dissolved in water. Similarly, he defined a base as a material that releases hydroxide ions (OH− ) when dissolved in water. This definition only held for ionic compounds containing hydrogen or hydroxide ions and did not apply to many acids and bases that we deal with today. Since this early definition of acids and bases was so limited, two more sophisticated and general definitions of acids and bases have since been developed, which are in wide use today. These are known as the Brønsted-Lowry definition and the Lewis definition.In 1923, both J.N. Brønsted of Denmark and Thomas Lowry of England, working independently, defined an acid as a species that can donate a hydrogen ion to a base. A base was defined as a species that can accept a hydrogen ion from an acid. So, a Brønsted-Lowry acid
eBook - PDF- David R. Klein(Author)
- 2021(Publication Date)
- Wiley(Publisher)
An understanding of the relevant reactions will lead to a greater appreci- ation of food chemistry. In this chapter, our study of acids and bases will serve as an introduction to the role of electrons in ionic reactions. An ionic reac- tion is a reaction in which ions participate as reactants, intermediates, or products. These reactions represent 95% of the reactions covered in this textbook. In order to prepare ourselves for the study of ionic reactions, it is critical to be able to identify acids and bases. We will learn how to draw acid-base reactions and to compare the acidity or basicity of compounds. These tools will enable us to predict when acid-base reactions are likely to occur and to choose the appropriate reagent to carry out any specific acid-base reaction. 3 94 CHAPTER 3 Acids and Bases DO YOU REMEMBER? Before you go on, be sure you understand the following topics. If necessary, review the suggested sections to prepare for this chapter. • Identifying Formal Charges (Sections 1.4 and 2.4) • Drawing and Interpreting Bond-Line Structures (Sections 1.6 and 2.2) • Identifying Lone Pairs (Section 2.5) • Drawing Resonance Structures (Section 2.10) Take the DO YOU REMEMBER? QUIZ in the online course to check your understanding. 3.1 Introduction to Brønsted-Lowry Acids and Bases This chapter will focus primarily on Brønsted-Lowry acids and bases. There is also a brief section dealing with Lewis acids and bases, a topic that will be revisited in Chapter 6 and subsequent chapters. The definition of Brønsted-Lowry acids and bases is based on the transfer of a proton (H + ). An acid is defined as a proton donor, while a base is defined as a proton acceptor. As an example, con- sider the following acid-base reaction: O Cl Cl Acid (proton donor) O Base (proton acceptor) H H H H H H + + - + In the reaction above, HCl functions as an acid because it donates a proton to H 2 O, while H 2 O functions as a base because it accepts the proton from HCl.
- Peter V. Hobbs(Author)
- 2000(Publication Date)
- Cambridge University Press(Publisher)
5 Acids and bases Very early in the history of chemistry many substances were designated as acids, bases, and salts. Acids have a sour taste (e.g., citric acid gives lemon juice its sour taste); they dissolve certain metals; and they also dissolve carbonate minerals to produce carbon dioxide. Bases have a bitter taste (e.g., sodium carbonate); they feel slippery when touched; and they react with many dissolved metal salts to form precipitates. However, the most striking characteristic of bases is their ability to neutralize the properties of acids; when a base reacts with an acid a salt is produced. The French chemist Lavoisier thought that all acids contain oxygen (the word oxygen means acid former in Greek). However, it was sub-sequently found that many acids contain no oxygen (e.g., hydrochloric acid, HC1), but that they all contain hydrogen. Acids and bases figure prominently in the equilibrium of aqueous solu-tions, where they significantly enhance the electrical conductivity of water. In this chapter, we will explore some of the important properties of acids and bases in aqueous solutions. This will lead us to a discussion of several theories of acids and bases. 5.1 Some definitions and concepts Equation (4.22) is valid for aqueous solutions as well as for pure water. A solution for which [H + (aq)] = [OH~(aq)] is said to be neutral; thus, pure water is neutral. If [H + (aq)] > [OH~(aq)] the solution is said to be acidic. If [OH(aq)] > [H + (aq)] the solution is said to be basic. Exercise 5.1. If 0.02 mole of hydrochloric acid is dissolved in 1L 1 of water, what are the concentrations of H + (aq) and OH(aq) ions I in the solution at 25°C? I 83 84 Acids and bases Solution. Hydrochloric acid is a gas under normal conditions, but it is a strong electrolyte that dissolves in water to form equal numbers of H + (aq) and Q(aq).
eBook - PDFChemistry
An Industry-Based Introduction with CD-ROM
- John Kenkel, Paul B. Kelter, David S. Hage(Authors)
- 2000(Publication Date)
- CRC Press(Publisher)
311 12 Acids and Bases 12.1 Introduction ....................................................................... 311 12.2 Formulas and Strengths of Acids and Bases .................... 311 12.3 Properties of Acids and Bases … ...................................... 315 General Properties • Properties of Some Specific Acids and Bases • “Add Acid to Water” Rule 12.4 Theories of Acids and Bases .............................................. 318 The Arrhenius Theory • The Bronsted-Lowry Theory • The Lewis Theory 12.5 Conjugate Acids and Bases ................................................ 320 12.6 Reactions Involving Acids and Bases ................................ 320 Neutralization • Reactions of Acids with Metals • Reaction of Metal and Nonmetal Oxides with Water • Reaction of Metal Oxides with Acids 12.7 Acidity Level: pH and pOH ............................................... 323 Water Ionization and the Ion Product Constant • pH • Logarithms • Significant Figures Rule • pOH • Relationship between pH and pOH • Calculations Summary 12.8 Measurement of pH ........................................................... 332 12.9 Homework Exercises .......................................................... 334 12.1 Introduction We have noted several times in previous chapters that over thirteen million chemical compounds exist. Because of this, the study of the chemistry (structure, composition, and properties) of these compounds can indeed be a formidable task. To simplify this task, the usual procedure is to divide and subdivide the compounds into various classifications and then to study individual classifications separately. This was our procedure with organic chemicals in Chapter 6. We have seen many classifications of compounds. We have seen gases, liquids, and solids, ionic and covalent compounds, inorganic and organic substances, polymeric and monomeric compounds, soluble and insoluble chemicals, and electrolytes and nonelectrolytes.
eBook - PDFChemistry
Structure and Dynamics
- James N. Spencer, George M. Bodner, Lyman H. Rickard(Authors)
- 2011(Publication Date)
- Wiley(Publisher)
468 Chapter Eleven ACIDS AND BASES 11.1 Properties of Acids and Bases 11.2 The Arrhenius Definition of Acids and Bases 11.3 The Brønsted–Lowry Definition of Acids and Bases 11.4 Conjugate Acid–Base Pairs 11.5 The Role of Water in the Brønsted Model 11.6 To What Extent Does Water Dissociate to Form Ions? 11.7 pH as a Measure of the Concentration of the H 3 O Ion 11.8 Relative Strengths of Acids and Bases 11.9 Relative Strengths of Conjugate Acid–Base Pairs 11.10 Relative Strengths of Different Acids and Bases 11.11 Relationship of Structure to Relative Strengths of Acids and Bases 11.12 Strong Acid pH Calculations 11.13 Weak Acid pH Calculations 11.14 Base pH Calculations 11.15 Mixtures of Acids and Bases: Buffers 11.16 Buffers and Buffer Capacity 11.17 Buffers in the Body 11.18 Acid–Base Reactions 11.19 pH Titration Curves Special Topics 11A.1 Diprotic Acids 11A.2 Diprotic Bases 11A.3 Compounds That Could Be Either Acids or Bases 11.1 Properties of Acids and Bases For more than 300 years, chemists have classified substances that behave like vinegar as acids and substances that have properties like wood ash as bases (or alkalies). The word acid comes from the Latin acidus, which means “sour,” and refers to the sharp odor and sour taste of many acids. Vinegar, for example, tastes sour because it is a dilute solution of acetic acid in water. Lemon juice tastes sour because it contains citric acid. Milk turns sour when it spoils because lactic acid is formed, and the unpleasant, sour odor of rotten meat or butter can be attrib- uted to compounds such as butyric acid that form when fat spoils. One of the characteristic properties of an acid is its ability to dissolve most metals. Zinc metal, for example, rapidly reacts with hydrochloric acid to form an aqueous solution of ZnCl 2 and hydrogen gas. Another characteristic property of acids is their ability to change the color of veg- etable dyes such as litmus.
eBook - PDFChemistry for Today
General, Organic, and Biochemistry
- Spencer Seager, Michael Slabaugh, Maren Hansen, , Spencer Seager, Spencer Seager, Michael Slabaugh, Maren Hansen(Authors)
- 2021(Publication Date)
- Cengage Learning EMEA(Publisher)
(Section 9.5) 6 Write reaction equations that illustrate the characteristic reactions of acids. (Section 9.6) 7 Write reaction equations that represent neutralization reactions between acids and bases. (Section 9.7) 8 Write reaction equations that illustrate various ways to prepare salts, and do calculations using the concept of an equivalent of salt. (Section 9.8) 9 Demonstrate an understanding of the words weak and strong as applied to acids and bases. (Section 9.9) SDI Productions/E+/Getty Images Copyright 2022 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Acids, Bases, and Salts 261 ACIDS, BASES, AND SALTS are among the most common and important sol- utes found in solutions. Until late in the 19th century, these substances were char- acterized by properties, such as taste and color changes induced in certain dyes. Acids taste sour (see Figure 9.1); bases, bitter; and salts, salty. Litmus, a dye, is red in the presence of acids and blue in the presence of bases. These and other obser- vations led to the correct conclusions that acids and bases are chemical opposites and that salts are produced when acids and bases react with each other. Today, acids and bases are defined in more precise ways that are useful when studying their characteristics. 9.1 The Arrhenius Theory Learning Objective 1 Write reaction equations that illustrate Arrhenius acid–base behavior. In 1887, Swedish chemist Svante Arrhenius proposed a theory dealing with electro- lytic dissociation. He defined an acid as a substance that dissociates when dissolved in water and produces hydrogen ions (H 1 ).
- Frederick Bettelheim, William Brown, Mary Campbell, Shawn Farrell(Authors)
- 2019(Publication Date)
- Cengage Learning EMEA(Publisher)
240 | Chapter 8 Acids and Bases Copyright 2020 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 8.6 Properties of Acids and Bases Today’s chemists do not taste the substances they work with, but 200 years ago they routinely did so. That is how we know that acids taste sour and bases taste bitter. The sour taste of lemons, vinegar, and many other foods, for example, is due to the acids they contain. A. Neutralization The most important reaction of acids and bases is that they react with each other in a process called neutralization. This name is appropriate be-cause, when a strong corrosive acid such as hydrochloric acid reacts with a strong caustic base such as sodium hydroxide, the product (a solution of ordinary table salt in water) has neither acidic nor basic properties. We call such a solution neutral. Section 8.9 discusses neutralization reactions in detail. B. Reaction with Metals Strong acids react with certain metals (called active metals) to produce hydrogen gas, H 2 , and a salt. Hydrochloric acid, for example, reacts with magnesium metal to give the salt magnesium chloride and hydrogen gas ( Figure 8.1 ). 1 Mg( s ) Magnesium MgCl 2 ( aq ) Magnesium chloride H 2 ( g ) Hydrogen 2HCl( aq ) Hydrochloric acid 1 The reaction of an acid with an active metal to give a salt and hydrogen gas is a redox reaction (Section 4.4). Both the acid and the salt formed are ion-ized in aqueous solution.
eBook - PDF- Douglas P. Heller, Carl H. Snyder(Authors)
- 2015(Publication Date)
- Wiley(Publisher)
Arrhenius definition of an acid In 1887, Arrhenius first defined an acid as any substance that produces hydrogen ions, H + , in water. For example, when hydrochloric acid (HCl) dissolves in water, it dissociates into hydrogen ion (H + ) and chloride ion (Cl - ). The H + bonds to H 2 O, forming H 3 O + , hydronium ion. c. Generality of the Brønsted-Lowry definition The Brønsted-Lowry definition of acids and bases is more general than that proposed by Arrhenius because it can apply to solutions of any kind, both aqueous and nonaqueous, as well as to gas-phase reactions, as shown here. b. Brønsted-Lowry definition of an acid The Arrhenius definition of acids and bases is restricted to aque- ous, or water-based, solutions. However, since aqueous solutions are commonly encountered in a wide variety of circumstances, including biological, environmental, and many industrial systems, the Arrhenius framework still has broad relevance. In 1923, Brønsted and Lowry independently proposed that acids donate hydrogen ions (protons or H + ) whereas bases accept them. "OEZ 8BTIOJL What’s that smoke? As ammonia vapors (NH 3 ) rise from one bottle, they meet hydrochloric acid vapors (HCl) ascending from the other. To- gether they form ammonium chloride (NH 4 Cl), which appears as a white smoke. This acid-base reaction takes place in the gas phase; it doesn’t require a solvent.
eBook - ePubA Mole of Chemistry
An Historical and Conceptual Approach to Fundamental Ideas in Chemistry
- Caroline Desgranges, Jerome Delhommelle(Authors)
- 2020(Publication Date)
- CRC Press(Publisher)
−3 mol/L.Maintaining a pH at a given level by adding or removing acids and bases is crucial for living organisms. This is, for instance, the case of the blood pH that, for humans, needs to stay in a very narrow range between 7.35 and 7.45. If the blood pH drops below 7.35, then a condition known as acidosis sets in. If the blood pH becomes greater than 7.45, the corresponding condition is called alkalosis. The key for the organism is to remove the carbon dioxide (or carbonic acid) produced by metabolizing glucose. This is achieved by the lungs which remove CO2 through breathing, and by the kidneys which remove it through urine. If the blood pH is not in the 7.35–7.45 range, there can be either a respiratory condition or a metabolic issue related to a dysfunction of the kidneys.Relative Strength and Chemical Hardness
Very early on, Lewis thinks that his theory can be applied to predict how acids and bases react with each other. In 1938, he writes in “Acids and Bases” that “The stronger acids combine with the stronger bases to form stable compounds, while the weaker acids do not usually form compounds with the weaker bases”. However, he quickly adds: “Such rough statements regarding the relative strength of acids and bases are useful, but are nevertheless likely to be misleading”. As examples for generalized bases, he considers the case of triethylamine N(C2 H5 )3 , pyridine C5 H5 N, acetone (CH3 )2 CO and ether C2 H5 OC2 H5 , arranged in the order of decreasing basic strength. Similarly, for acids, he studies several examples: sulfur trioxide SO3 , boron trichloride BCl3 , stannic chloride SnCl4 , silver perchlorate AgClO4 , sulfur dioxide SO2 and carbon dioxide CO2 , arranged in the order of decreasing acid strength. However, he observes several puzzling facts. For instance, he finds that the silver ion behaves as a weak acid towards the hydroxyde ion. However, adding ammonia to the solution increases the reactivity of the silver ion, which now behaves as a strong acid towards hydroxyde. Furthermore, he finds that weak acids and bases can form stable complexes: “SO2 is a weak acid and I− and SCN− are weak bases but both these anions form fairly stable complexes with SO2
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