Chemistry
Neutralisation Reaction
Neutralisation reaction is a chemical reaction between an acid and a base, resulting in the formation of water and a salt. The reaction involves the transfer of protons from the acid to the base, leading to the neutralization of their acidic and basic properties. This process is commonly used to neutralize the effects of acidic or basic substances.
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10 Key excerpts on "Neutralisation Reaction"
eBook - PDF- Morris Hein, Susan Arena, Cary Willard(Authors)
- 2021(Publication Date)
- Wiley(Publisher)
Therefore the equation for the neutraliza- tion can be written as this net ionic equation: H + (aq) acid + OH − (aq) base ⟶ H 2 O (l) water This simple net ionic equation represents not only the reaction of sodium hydroxide and hydrochloric acid but also the reaction of any strong acid with any water‐soluble hydroxide base in an aqueous solution. The driving force of a neutralization reaction is the ability of an H + ion and an OH − ion to react and form a molecule of water. The amount of acid, base, or other species in a sample can be determined by titration, which measures the volume of one reagent required to react with a measured mass or volume of another reagent. Consider the titration of an acid with a base shown in Figure 15.6. A measured volume of acid of unknown concentration is placed in a flask, and a few drops of an indicator solution are added. Base solution of known concentration is slowly added from a buret to the acid until the indicator changes color. The indicator selected is one that changes color when the stoichiometric quantity (according to the equation) of base has been added to CHECK YOUR UNDERSTANDING 15.3 Acid and Base Combinations That Form Salts 376 CHAPTER 15 Acids, Bases, and Salts the acid. At this point, known as the end point of the titration, the titration is complete, and the volume of base used to neutralize the acid is read from the buret. The concentration or amount of acid in solution can be calculated from the titration data and the chemical equation for the reaction. Let’s look at some examples. CHECK YOUR UNDERSTANDING 15.14 Titration Before colorless and clear End point pale pink persists After end point bright pink (excess base) Richard Megna/Fundamental Photographs Richard Megna/Fundamental Photographs Richard Megna/Fundamental Photographs FIGURE 15.6 The titration process with phenolphthalein indicator. Phenolphthalein, an organic compound, is colorless in acid solution and changes to pink at a pH of 8.3.
eBook - PDF- Leo J. Malone, Theodore O. Dolter(Authors)
- 2012(Publication Date)
- Wiley(Publisher)
The products of such a reaction are a salt and water. We will look at the interactions of solutions of acids with solutions of bases next. ■ In Chapter 6 we described a type of double-displacement reaction between acids and bases known as neutralization. If we mix the acid and base in stoichiometric amounts, the products are simply water and a salt. We will begin our discussion of neutralization reactions with a review of the reaction between a strong acid (hydro- chloric acid) and a strong base (sodium hydroxide) as described in Chapter 6 and then move on to other cases. The molecular, total ionic, and net ionic equations are shown below. In this case, it is more convenient to represent the acid species as simply H + (aq) rather than H 3 O + . ACID + BASE ¡ SALT + WATER Molecular: HCl(aq) + NaOH(aq) ¡ NaCl(aq) + H 2 O(l) Total ionic: H + (aq) + Cl - (aq) + Na + (aq) + OH - (aq) ¡ Na + (aq) + Cl - (aq) + H 2 O(l) Net ionic: H + (aq) + OH - (aq) ¡ H 2 O(l) The key to what drives neutralization reactions is found in the net ionic equation. The active ingredient from the acid [H + (aq)] reacts with the active ingredient from the base [OH - (aq)] to form the molecular compound water. A salt is what is left over—usually present as spectator ions if the salt is soluble. As a vital mineral needed to maintain good health, “salt” refers to just one sub- stance, sodium chloride, as formed in the preceding reaction. Actually, salts can result from many different combinations of anions and cations from a variety of neutralizations. The following neutralization reactions, written in molecular form, illustrate the formation of some other salts. C C OBJECTIVE FOR SECTION 13-4 Write the molecular, total ionic, and net ionic equations for neu- tralization reactions. EXERCISE 13-3(a) LEVEL 1: Fill in the blanks. Strong acids are essentially _______% ionized in aqueous solution, whereas weak acids are _______ ionized. Sodium hydroxide is a strong base, but ammonia is a _______.
eBook - PDF- Morris Hein, Susan Arena, Cary Willard(Authors)
- 2016(Publication Date)
- Wiley(Publisher)
The following total ionic equation gives a better representation of the reaction: (H + + Cl − ) + (Na + + OH − ) ⎯→ Na + + Cl − + H 2 O(l ) This equation shows that the Na + and Cl − ions did not react. These ions are called spectator ions because they were present but did not take part in the reaction. The only reaction that occurred was that between the H + and OH − ions. Therefore the equation for the neutralization can be written as this net ionic equation: H + (aq) + OH − (aq) ⎯→ H 2 O(l ) acid base water This simple net ionic equation represents not only the reaction of sodium hydroxide and hydrochloric acid but also the reaction of any strong acid with any water-soluble hydrox- ide base in an aqueous solution. The driving force of a neutralization reaction is the abil- ity of an H + ion and an OH − ion to react and form a molecule of water. The amount of acid, base, or other species in a sample can be determined by titra- tion, which measures the volume of one reagent required to react with a measured mass or volume of another reagent. Consider the titration of an acid with a base shown in FIGURE 15.6. A measured volume of acid of unknown concentration is placed in a flask, and a few drops of an indicator solution are added. Base solution of known concentration is slowly added from a buret to the acid until the indicator changes color. The indicator selected is one that changes color when the stoichiometric quantity (according to the equation) of base has been added to the acid. At this point, known as the end point of the titration, the titration is complete, and the volume of base used LEARNING OBJECTIVE KEY TERMS neutralization spectator ion titration CHECK YOUR UNDERSTANDING 15.13 Acid and Base Combinations That Form Salts ➥ 358 CHAPTER 15 • Acids, Bases, and Salts to neutralize the acid is read from the buret. The concentration or amount of acid in solution can be calculated from the titration data and the chemical equation for the reaction.
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)
− and is evidently independent of the nature of the acid and the base. The development of heat in any reaction of this kind must therefore always be the same for equivalent quantities of any acids and bases”. He also finds that this heat of neutralization is always equal to 13,600 calories at 18°C!FIGURE 5.3 Sodium ion in an aqueous solution.Now, let us look at water. Following what precedes, water should dissociate into H+ and OH− , or in other words, H2 O → H+ + OH− . This equation is also known as hydrolysis. This means that H2 O is both an acid and a base, since it releases H+ and OH− ! However, Arrhenius states that “water is hardly dissociated at all” meaning that “water can be regarded as a weak acid or base”. He thus introduces the concept of weak acids and weak bases to account for compounds that do not entirely dissociate in water. On the other hand, strong acids or bases are compounds that completely dissociate in water. For example, HCl, HNO3 , H2 SO4 and HClO4 are strong acids, while NaOH, KOH, LiOH and Ca(OH)2 are strong bases. As for weak acids, we have acetic acid H3 COOH which partially dissociates into CH3 COO− and H+ . The equation is then written as H3 COOH = CH3 COO− + H+ . Here the sign “=” shows the partial dissociation, while the sign “→” is usually used for a complete dissociation. Another example is phosphoric acid H3 PO4 which gives H3 PO4 = H2 PO4 − + H+ . Regarding weak bases, we have ammonium hydroxide NH4 OH which dissociates into NH4 OH = NH4 + + OH−
eBook - ePub- Clyde Frank(Author)
- 2012(Publication Date)
- Academic Press(Publisher)
Chapter EightNeutralization in Analytical Chemistry
Publisher Summary
Analytical procedures that are based on neutralization between an acid and a base have been used extensively in volumetric analysis. By this procedure, many inorganic and organic acids and bases can be determined with a high degree of precision and accuracy. The procedure involves the dissolution of the acidic or basic sample and subsequent titration of the solution with a standard basic or acidic titrant. This chapter focuses on the applications to analysis and the principles of neutralization. It discusses strong and weak acids and bases, conjugate acid-base systems, buffer systems, expression and calculation of the hydronium ion concentration (pH) for a system, and applications in quantitative analysis. Because a stoichiometric neutralization reaction involves passing from an acidic to basic solution, assuming an acid is being titrated with a base, the progress of the reaction is followed by determining the pH of the solution as a function of an added titrant.INTRODUCTION
Analytical procedures based on neutralization between an acid and a base have been used extensively in volumetric analysis. By this procedure, many inorganic and organic acids and bases can be determined with a high degree of precision and accuracy. In general, the procedure entails the dissolution of the acidic or basic sample and subsequent titration of the solution with a standard basic or acidic titrant, respectively.
- Martha Mackin(Author)
- 2012(Publication Date)
- Academic Press(Publisher)
14.6 h. Understanding the process of acid-base neutralization. 356 Chapter 14 Topical Outline 357 14.6 i. Ability to write the names and formulas of the salts formed in acid-base neutralizations, j. Understanding the laboratory procedure used in titration, k. Using hydrolysis to explain why the solutions of some salts are acidic and others are basic. 1. Understanding how a buffer maintains the pH of a solution within a very narrow range. 3. Types of numerical exercises that should be mastered: Number of related textbook objective 14.5 14.7 and in the supple-ment to Chapter 14 a. Calculating pH from hydronium ion concentration and calculating hydronium ion concentration from pH. b. Calculating the concentration of an acid or a base using data obtained from a titration procedure; solving the problem by using molarity or normality (see supplement) CHAPTER 14 TOPICAL OUTLINE I. Definitions and properties of acids and bases 14.1 Acids A. Water can self-ionize. 1. It produces one hydrogen ion and one hydroxide ion: H 2 0(1) • H + (aq) + OH-(aq) water hydrogen hydroxide ion ion 2. In pure water the concentration of both the Η and the OH is 1.0 χ 10~ 7 M. B. Arrehenius defined an acid as an electrolyte that furnishes Η ions in a water solution. + C. Bronsted-Lowry defined an acid as a proton donor (the Η is a proton). 1. In water solution the proton combines with water to form a hydrated hydrogen ion, which is called a hydronium ion (ΗβΟ 1 ); for example: HCl(g) + H 2 0(1) • H 3 0 + (aq) + Cl(aq) hydrogen water hydronium chloride chloride ion ion 2. The properties of acids depend on the H + whether it is represented as H + or as H 3 0 + . 3. For example: HCl(g) + H 2 0(1) • H 3 0 + (aq) + Cl(aq) hydrogen water hydronium chloride chloride + ion ion a) A proton (H ) is transferred from the acid molecule, HCl, to water. b) A hydrated proton or a hydronium ion (H 3 0 ) is formed; the re-sulting solution has the properties of an acid, in this case hydrochloric acid.
eBook - PDFFoundations of Chemistry
An Introductory Course for Science Students
- Philippa B. Cranwell, Elizabeth M. Page(Authors)
- 2021(Publication Date)
- Wiley(Publisher)
An example of this might be the reaction of hydrochloric acid with sodium hydroxide to produce sodium chloride and water: HCl aq + NaOH aq NaCl aq + H 2 O l acid base salt water For any monoprotic acid, the overall ionic equation for reaction with a base is the same. If the aqueous species are written in their dissociated states, we have the following equation, and the ions that are present on both sides can be can-celled out: H + aq + Cl − aq + Na + aq + OH − aq Na + aq + Cl − aq + H 2 O l This leaves the ionic equation for the acid-base reaction H + aq + OH − aq H 2 O l that represents the chemical process that takes place when an acid and base react together. Always think about the answer. You know this is a strong base and will therefore have a high pH and a low pOH. –––––– ––––––– –––––– ––––––– 236 Chemical equilibrium and acid-base equilibrium In an acid-base titration, an acid reacts with a base under controlled condi-tions. A titration is used to determine the concentration or amount in moles of either the acid or the base, knowing the amount in moles of the other reactant. 7.3.6 Carrying out a titration The apparatus for carrying out a titration is shown in Figure 7.7. An acid of known concentration is added to the burette. An accurately measured volume of base, whose concentration is to be determined, is added to the conical flask. The acid in the burette is run into the flask and the solution swirled to mix. When just enough acid has been added to the base to completely neutralise it, the titra-tion is stopped. The volume of acid added is noted and used to calculate the con-centration of the base. Alternatively, the burette is filled with base which is added to the acid in the flask until just neutralised. Accurate values of pH changes occurring during an acid-base titration can be monitored using a pH meter (Figure 7.6).
- Morris Hein, Susan Arena, Cary Willard(Authors)
- 2022(Publication Date)
- Wiley(Publisher)
230 CHAPTER 15 ACIDS, BASES, AND SALTS SOLUTIONS TO REVIEW QUESTIONS 1. The Arrhenius definition is restricted to aqueous solutions, while the Brønsted- Lowry definition is not. 2. By the Arrhenius theory, an acid is a substance that produces hydrogen ions in aqueous solution. A base is a substance that produces hydroxide ions in aqueous solution. By the Brønsted-Lowry theory, an acid is a proton donor, while a base accepts protons. Since a proton is a hydrogen ion, then the two theories are very similar for acids, but not bases. A chloride ion can accept a proton (producing HCl), so it is a Brønsted-Lowry base, but would not be a base by the Arrhenius theory, since it does not produce hydroxide ions. By the Lewis theory, an acid is an electron pair acceptor, and a base is an electron pair donor. Many individual substances would be similarly classified as bases by Brønsted-Lowry or Lewis theories, since a substance with an electron pair to donate, can accept a proton. But, the Lewis definition is almost exclusively applied to reactions where the acid and base combine into a single molecule. The Brønsted- Lowry definition is usually applied to reactions that involve a transfer of a proton from the acid to the base. The Arrhenius definition is most often applied to individual substances, not to reactions. According to the Arrhenius theory, neutralization involves the reaction between a hydrogen ion and a hydroxide ion to form water. Neutralization, according to the Brønsted-Lowry theory, involves the transfer of a proton to a negative ion. The formation of a covalent bond constitutes a Lewis neutralization. 3. Neutralization reactions: ( ) − + → + + → + 2 2 Arrhenius: HCl NaOH NaCl H O H OH H O Brønsted-Lowry: ( ) + − + → + + → HCl KCN HCN KCl H CN HCN Lewis: − + + → + 3 4 AlCl NaCl AlCl Na 4. These ions are considered to be bases according to the Brønsted-Lowry theory, because they can accept a proton at any of their unshared pairs of electrons.
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 ).
- Peter V. Hobbs(Author)
- 2000(Publication Date)
- Cambridge University Press(Publisher)
1 It follows from the above definitions that acids and bases have opposite (or opposing) tendencies. Thus, bases react with acids to neutralize their acidity. For example, two neutralizing reactions are HC1 + NaOH -> H 2 O + NaCl H 2 SO 4 + CaO -> H 2 O + CaSO 4 In both cases, an acid reacts with a base to produce water and a third class of substance called a salt (e.g., NaCl and CaSO 4 ). The acidity (or alkalinity, as the case may be) of an aqueous solution is very important because H + (aq) and OH (aq) ions play crucial roles in many reactions in aqueous solutions. For example, the acidity (or alka-linity) determines the ability of water to sustain fish and plant life; it also determines the solubility of many materials in water. In addition to the acids we have already mentioned, some other common acids are sulfuric acid (H 2 SO 4 ), nitric acid (HNO 3 ), formic acid Some definitions and concepts 85 (HCOOH), phosphoric acid (H 3 PO 4 ), hydrogen fluoride (HF), hydro-bromic acid (HBr), hydroiodic acid (HI), and perchloric acid (HC1O 4 ). Based on the discussion so far, we might hypothesize that acids have the following properties in common: they contain hydrogen, they dissolve in water to produce ions that conduct electricity (i.e., they are electrolytes), and one of the ions they release is H + (aq). Some common bases are sodium hydroxide (NaOH), potassium hydroxide (KOH), magnesium hydroxide (Mg(OH) 2 ), calcium oxide (CaO), sodium carbonate (Na 2 CO 3 ), and ammonia (NH 3 ).We could pos-tulate that, like acids, a common property of bases is their ability to dis-solve in water to produce ions. Also, since bases counteract acids, we might conclude that one of the ions they produce can remove the hydro-gen ion. For NaOH, KOH, and Mg(OH) 2 this ion is clearly OH(aq). But what is it for Na 2 CO 3 and NH 3 ? To answer this question let us consider what happens when ammonia dissolves in water.
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