21. Acids/Bases Biology /Chemistry. acids/bases. Chandra E. Price. Burnham/Anthony Inclusive. 10516 S. Wood St. 1903 East 96 Street. Chicago IL 60643. Chicago IL 60617 ( 773) 535 6530. Objective(s) distinguish http://www.iit.edu/~smile/cb1398.htm

Biology /Chemistry Acids/Bases Chandra E. Price Burnham/Anthony Inclusive 10516 S. Wood St. 1903 East 96 Street Chicago IL 60643 Chicago IL 60617 Objective(s) The student will be able to: 1) distinguish between the differences of acids/bases, 2) demonstrate how to test for acids and bases, and 3) communicate the significance of testing for acids and bases. Materials Needed Detergent-quart, shampoo- quart Lemon-juice-quart Milk-quart Orange-juice-quart Tomato-juice-quart Baking-soda Salt-shaker Peroxide-quart Red-cabbage-small Apple-juice Containers-plastic-25 Hot plate distilled water Paper towels eye droppers station signs Pepto Bismol acid rain paper towels Markers spoons antacid tablets Pickle juice large containers transparent containers Safety glasses pot holders aprons Vocabulary Acid, base, chemistry, indicator Strategies Strategy 1 Introduction: What you Know, What you will Learn What you have learned.). Strategy 2 Dramatization: Traditional vs. Phenomenological Ms. Traditional asked her students to read and answer questions about acids and bases. She gave little explanation and no hands on activities for the students to become involved. When she went over the assignment the majority of the class did not complete the assignment. However, in Ms. Phenomenological the atmosphere was different. She began eating an orange and indicated that her mouth was burning. She asked the students what they thought her problem was? Someone responded, "there might be too much acid in that orange". What a great statement! Then, she states, "we are going to learn about acids and bases."

22. ThinkQuest : Library : CHEMystery - Interactive Guide To Understanding Chemistry acids and bases. Return to the acids and bases Page. = Back Next = acids and basesrelate to each other in Conjugate Pairs, somewhat like husbands and wives. http://library.thinkquest.org/3659/acidbase/acidsandbases.html

Index Physical Science Chemistry CHEMystery - Interactive Guide to Understanding Chemistry Everything a high school student needs to know about chemistry is at this site in a fun, imaginative, comprehensive presentation that catches the eye. Find a periodic table that looks and acts differently than any you've seen before. Research atoms, molecules, organic chemistry, equilibriums, acids and bases, nuclear reactions and more. This excellent site claims to be a virtual text book and that's not an empty promise. Even if you don't like chemistry, check out this site. Languages: English. Visit Site 1996 ThinkQuest Internet Challenge Awards GEM Languages English Students Clyde Ward Melville High School, East Setauket, NY, United States Gaurav Ward Melville High School, East Setauket, NY, United States Christopher Brentwood High School Ross Building, Brentwood, NY, United States Coaches Melanie Ward Melville High School, Setauket, NY, United States John Brentwood High School Ross Building, Brentwood, NY, United States Want to build a ThinkQuest site?

23. Acids, Bases And PH acids, bases and pH. An updated version of this lesson is available at Visionlearningacids bases. Acidbase chemistry is an important part of everyday life. http://web.jjay.cuny.edu/~acarpi/NSC/7-ph.htm

Acids, Bases and pH An updated version of this lesson is available at Visionlearning: Water is a funny substance. It makes possible much of the chemistry that goes on in our bodies and all around us. But most people take for granted the chemical properties of water. We've already learned that water molecules are constantly in motion. And keep in mind that each water molecule carries a dipole, or net charge, across the molecule. As we saw in the atomic bonding lesson, this dipole causes each molecule to behave like a little magnet with a positive and negative end. This dipole causes water molecules to be attracted to each other; the positive hydrogen is attracted to the negative oxygen of a nearby molecule. The MathMol Water and Ice page has put together an excellent simulation of the attraction between 2 water molecules that you can view by clicking here (~160k movie) (Note: white = H, red = O). Because the oxygen atom in water tends to monopolize the electrons in the molecule, the hydrogen protons are only loosely held to the molecule. The attraction between adjacent water molecules allows them to swap hydrogen protons. In fact, many molecules that contain hydrogen can swap protons with water molecules. A simulation of a proton transfer between a molecule of water and a molecule of formic acid is available by clicking here (~158k; white = H, red = O).

24. Acids And Bases acids and bases. Read this standardized test practice passage and answer the questions. (28 min). There are three theories used to define acids and bases. http://www.howe.k12.ok.us/~jimaskew/cacid.htm

Chemistry Week 24 Day 1 Day 2 Day 3 - 4 Lab 1 ... Reading Assignment This Week's Process Standards: 1.1, 1.2, 1.3, 2.1, 2.2, 3.1, 3.3, 3.4, 3.5, 4.1, 4.2, 4.4, 4.5, 4.6, 4.7, 6.3, 6.4 Content Standards: 1.4, 2.1, 2.4 Instructional Technology Standards: 4.2, 5.2 Use the three acid-base theories to identify acids and bases under different conditions. Write the names of binary acids. Write the names of ternary acids. Write the anhydrous form of ternary acids. Predict whether an oxide is an acid anhydride or a basic anhydride. Use the formula of an acid to determine if it is strong or weak. Use factor-label for titration calculations. Acids and Bases Read this standardized test practice passage and answer the questions. You have seven minutes to complete the assignment. (28 min) There are three "theories" used to define acids and bases. Each of these theories focuses on a slightly different property. As you go down the list, the definition broadens to include a wider range of substances. 1. Arrhenius Theory: Acid - produces hydrogen ions, H

25. Chemistry (ACC Riverside Campus) - Relative Strengths Of Acids And Bases Relative Strengths of acids and bases. Acid, Ionization Reaction, Ki. Perchloric Acid, HClO 4 H + + ClO 4 , Hydroiodic Acid, HI H + +I -, http://www.austin.cc.tx.us/rvsmthsc/chem/chem-Relative.html

Relative Strengths of Acids and Bases Acid Ionization Reaction K i Perchloric Acid HClO H + ClO Hydroiodic Acid HI H + I Hydrobromic Acid HBr H + Br Hydrochloric Acid HCl H + Cl Nitric Acid HNO H + NO Sulfuric Acid H SO H + HSO Oxalic Acid H C O H + HC O 5.4 x 10 Sulfurous Acid H SO H + HSO 1.7 x 10 Hydrogen Sulfate Ion HSO H + SO 1.3 x 10 Phosphoric Acid H PO H + H PO 7.1 x 10 Hydrofluoric Acid HF H + F 6.7 x 10 Nitrous Acid HNO H + NO 5.1 x 10 Benzoic Acid C H COOH H + C H COO 6.6 x 10 Hydrogen Oxalate Ion HC O H + C O 5.4 x 10 Acetic Acid HC H O H + C H O 1.8 x 10 Carbonic Acid H CO H + HCO 4.4 x 10 Hydrogen Sulfide H S H + HS 1.0 x 10 Dihydrogen Phosphate Ion H PO H + HPO 6.3 x 10 Hydrogen Sulfite Ion HSO H + SO 6.2 x 10 Hydrocyanic Acid HCN H + CN 4.9 x 10 Ammonium Ion NH H + NH 5.7 x 10 Hydrogen Carbonate Ion HCO H + CO 4.7 x 10 Hydrogen Peroxide H O H + HO 2.4 x 10 Monohydrogen Phosphate Ion HPO H + PO 4.4 x 10 Hydrogen Sulfide Ion HS H + S 1.3 x 10 Water H O H + OH 1.0 x 10 Hydroxide Ion OH H + O 1 x 10 Ammonia NH H + NH very small Base Ionization Reaction K i Ammonium Hydroxide NH OH NH + OH 1.8 x 10

26. Acids And Bases acids and bases. acids are substances that donate protons (hydrogen ions,H + ) to bases. bases are substances that accept protons from acids. http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/A/Acids_Bases.html

Acids and Bases Acids are substances that donate protons (hydrogen ions, H ) to bases. Bases are substances that accept protons from acids. Let's look at an example. Hydrogen chloride (HCl) is a gas. Its two atoms are held together by a shared pair of electrons. However, the chlorine atom is so much more electronegative than hydrogen, that the bond between them is polar covalent Link to a discussion of electronegativity and its role in bond formation. When hydrogen chloride is bubbled through water, the nucleus of the hydrogen atom leaves and takes up residence at one of the unshared pairs of electrons in the water molecule. However, its electron remains behind still attached to the chlorine atom. This ionization produces: a chloride ion (Cl a hydronium ion (H O The resulting mixture is called hydrochloric acid Now let us bubble ammonia gas (NH ) through the hydrochloric acid. Ammonia molecules have one pair of unshared electrons and these have a greater affinity for a proton than do the unshared electrons in the water molecule. Consequently, the proton shifts again ( ) to form a new ion, the

27. Chapter 12 - Acids And Bases Chapter 12 acids and bases. I. Properties of acids and bases. acids.Taste sour; II. Reaction of acids and bases with water acids and http://virtual.yosemite.cc.ca.us/lmaki/Chem142/chap_outlines/chapter12.htm

Chapter 12 - Acids and Bases I. Properties of Acids and Bases ACIDS Taste sour Reach with certain metals (Zn, Fe, etc.) to produce hydrogen gas cause certain organic dyes to change color react with limestone (CaCO3) to produce carbon dioxide React with bases to form salts and water BASES Taste bitter feel slippery or soapy react with oils and grease cause certain organic dyes to change color react with acids to form salts and water Define: Acid - a substance that produces protons, H Base - a substance that produces hydroxide ions, OH II. Reaction of acids and bases with water: Acids and bases form ions in solution: HCl(aq) H (aq) + Cl (aq) H O hydronium ion H and H O are equivalent in aq. solution When we look at the reactions of acids - can be generalized using hydrogen ion Reaction with zinc yields hydrogen gas Reaction with limestone - produce CO2(g) Acids react with bases to produce a salt Similarly for bases, produce hydroxide ions III. Neutralization and Salts

28. Acids And Bases - PH Chemistry Search. Chemistry, acids and bases Guide picks. Acid and Base Definitions Your Guidepresents Arrhenius, BronstedLowry, and Lewis definitions of acids and bases. http://chemistry.about.com/cs/acidsandbases/

zJs=10 zJs=11 zJs=12 zJs=13 zc(5,'jsc',zJs,9999999,'') About Homework Help Chemistry General Chemistry ... Chemistry Glossary zau(256,152,145,'gob','http://z.about.com/5/ad/go.htm?gs='+gs,''); General Chemistry Branches of Chemistry Demos / Experiments Homework Help ... Help zau(256,138,125,'el','http://z.about.com/0/ip/417/0.htm','');w(xb+xb); Stay Current Subscribe to the About Chemistry newsletter. Search Chemistry Acids, Bases, and pH Here are lecture notes, tutorials, definitions, study guides, tables, self-quizzes and other resources to make those acid-base and pH problems easier. Alphabetical Recent Up a category Acid-Base Indicators Learn what an acid-base indicator is and how it works. A table is provided with names of indicators, pH indicator ranges, indicator concentrations in water or alcohol, and colors. Acid and Base Definitions Your Guide presents Arrhenius, Bronsted-Lowry, and Lewis definitions of acids and bases. Lists of properties of acids and bases and common examples are provided. Chemistry Fun with Pennies Use pennies, nails, and a few simple household ingredients to explore some of the interesting properties of metals. Clean the pennies chemically, make verdigris, and plate the nails with copper. Home and Garden pH Indicators Here's a list of common household substances and garden plants that can be used as pH indicators. Many of the active molecules, expected color changes, and pH ranges are listed.

29. Acid And Base Terms And Concepts Search. Chemistry acids and bases. Terms and Concepts. There are severalmethods of defining acids and bases. While these definitions http://chemistry.about.com/library/weekly/blacidbase.htm

zJs=10 zJs=11 zJs=12 zJs=13 zc(5,'jsc',zJs,9999999,'') About Homework Help Chemistry Home ... Chemistry Glossary zau(256,152,145,'gob','http://z.about.com/5/ad/go.htm?gs='+gs,''); General Chemistry Branches of Chemistry Demos / Experiments Homework Help ... Help zau(256,138,125,'el','http://z.about.com/0/ip/417/0.htm','');w(xb+xb); Stay Current Subscribe to the About Chemistry newsletter. Search Chemistry Acids and Bases Terms and Concepts Related Resources Acids and Bases CHEM 101 Chemistry Glossary From Other Guides Physics Homework/Study Tips Biology There are several methods of defining acids and bases. While these definitions don't contradict each other, they do vary in how inclusive they are. Antoine Lavoisier, Humphry Davy, and Justus Liebig also made observations regarding acids and bases, but didn't formalize definitions. Svante Arrhenius acids produce H ions in aqueous solutions bases produce OH ions in aqueous solutions water required, so only allows for aqueous solutions only protic acids are allowed; required to produce hydrogen ions only hydroxide bases are allowed acids are proton donors bases are proton acceptors aqueous solutions are permissible bases besides hydroxides are permissible only protic acids are allowed Gilbert Newton Lewis acids are electron pair acceptors bases are electron pair donors least restrictive of acid-base definitions Properties of Acids taste sour (don't taste them!)... the word 'acid' comes from the Latin

30. Acids And Bases acids and bases an acid is any compound or ion which yields hydrogen ions in watersolution and a base is any compound or ion which yields hydroxyl ions in http://www.chemistry.co.nz/acids_and_bases.htm

Previous Level Chemistry Defined Time Capsule Famous Scientists [ Acids and Bases ] Redox Reactions Equations What is a Mole? Cooking at Altitude ... Links Acids and Bases Acids and Bases Take the quiz then check your grading. Excellent resource! CHEMystery: Acids and Bases One of the best information resources ChemTeam: Acid Base Very comprehensive tutorials. A calculator is required for the problem solving areas! W.J. Mouat Chemistry 12 Home Page This web page was produced by Mark Iannone, who is a Chemistry teacher at W. J. Mouat Secondary School in Abbotsford, B.C. Canada. Review questions and answers are provided for each unit in Chemistry 12. Scholarship level questions, which are more challenging, and answers are also provided. Explanations of Acid-Base Behavior The first quantitative approach to acid-base equilibria was developed around 1884 by the Swedish chemist Svante Arrhenius. According to his Arrhenius theory, an acid is any compound or ion which yields hydrogen ions in water solution and a base is any compound or ion which yields hydroxyl ions in water solution. Acids, Bases, and Salts

31. Properties Of Acids And Bases Properties of acids and bases. Observable Properties. (You may rememberdoing this in lesson 1 of CH104.). Identifying acids and bases. http://dl.clackamas.cc.or.us/ch105-05/properti.htm

Properties of Acids and Bases Observable Properties One purpose of this lesson is for you to become familiar with many aspects of acids and bases. Let's start with some of the observable properties of acids and bases. Take a look at exercise 2 in your workbook. In this exercise you will test the reaction of an acid and a base with the various chemicals listed here. For the acid use 1 molar hydrochloric acid (1M HCl). For the base use 1 molar sodium hydroxide (1M NaOH). The video clip to the right shows the reaction of an acid with blue litmus paper (left) and then with pH paper (right). To start the video clip move your mouse over the image. (You do not need to click.) The video clip to the right shows the reaction of a base with red litmus paper (left), then with phenolphthalien (center), and then with pH paper (right). To start the video clip move your mouse over the image. (You do not need to click.) When you are in the lab you will perform these tests and the others in the exercise, then record the results in the blank spaces on the chart. When you have completed exercise 2, you will have experimented with several properties of acids and bases. Those properties give you a variety of ways that can be used to test whether a material is an acid or a base (which comes up in exercise 4). Let me take a minute to touch on a few of them.

32. Acids And Bases Table of Contents. http://www.okstate.edu/jgelder/acidandbase.html

Table of Contents

33. Weak Acids And Bases CAcT HomePage Weak acids and bases. Skills to develop. Define a weakacid or base. Calculate the pH or pOH quickly. Weak acids and bases. http://www.science.uwaterloo.ca/~cchieh/cact/c123/wkacids.html

CAcT HomePage Weak Acids and Bases Skills to develop Define a weak acid or base. Calculate pH and pOH of a weak acid or base solution using simple formula, quadratic equation, and including autoionization of water. Calculate the pH or pOH quickly. Weak Acids and Bases Weak acids and bases are only partially ionized in their solutions, whereas strong acids and bases are completely ionized when dissolve in water. Common Weak Acids Acid Formula Formic HCOOH Acetic CH COOH Trichloroacetic CCl COOH Hydrofluoric HF Hydrocyanic HCN Hydrogen sulfide H S Water H O Conjugate acids of weak bases NH Common Weak Bases Base Formula ammonia NH trimethyl ammonia N(CH pyridine C H N ammonium hydroxide NH OH water H O HS ion HS conjugate bases of weak acids e.g.: HCOO Some common weak acids and bases are given here. Furthermore, weak acids and bases are very common, and we encounter them often both in the academic problems and in everyday life. The ionization of weak acids and bases is a chemical equilibrium phenomenon. The equilibrium principles are essential for the understanding of equilibria of weak acids and weak bases. The conjugate acid-base pairs have been discussed in Acids and Bases . In this connection, you probably realize that

34. Strong Acids And Bases Strong acids and bases. Skills to develop. Strong acids and bases. The animationhere shows the formation of H 3 + O ions and OH ions in an aqueous system. http://www.science.uwaterloo.ca/~cchieh/cact/c123/stacids.html

CAcT HomePage Strong Acids and Bases Skills to develop Give the names and formulas of some strong acids and bases. Explain the pH scale, and convert pH and [HSUP>+ Evaluate solution pH and pOH of strong acids or bases. Strong Acids and Bases The animation here shows the formation of H O ions and OH ions in an aqueous system. Acids and bases that are completely ionized when dissolved in water are called strong acids and strong bases There are only a few strong acids and bases, and everyone should know their names and properties. These acids are often used in industry and everyday life. The concentrations of acids and bases are often expressed in terms of pH, and as an educated person, you should have the skill to convert concentrations into pH and pOH. The pH is an indication of the hydrogen ion concentration, [H Strong Acids Strong acids Type Formula Hydrogen halides HCl HBr HI Oxyacids of halogens, HClO HClO HBrO HBrO HIO HIO Sulfuric acid H SO Nitric acid HNO Strong acids are acids that are completely or nearly 100% ionized in their solutions. Here are some common strong acids: Ionization of a strong acid HA can be represented by: HA = H + A x x where x is the concentration of H , [H ]. For a strong acid, [H

35. Acids, Bases, And Salts acids, bases, and SaltsIonic Equilibria. This page begins the attempt WidenerUniversity.). acids and bases by ChemTeam. RH Logan, Instructor http://members.aol.com/logan20/ionic_eq.html

Acids, Bases, and Salts-Ionic Equilibria This page begins the attempt of this author to offer some notes that have previously been found either on a chalkboard or an overhead projector. If you find that the notes offer a clear understanding of the underlying concepts, then this Web complex will have been worth it. Please send me e-mail if you have any suggestions or comments. If you click on an option and it doesn't connect, it is probably because that page is under heavy construction and is unavailable at the time. Try again later!! Click one of the following: Concepts To Check Acid/Base Definitions Acid Strength And Molecular Structure pH, pOH, And pK w ... , and Hydrolysis Of Salts Not available yet Acid/Base Titration Slightly Soluble Salts and K sp Determination ... Acid-Base Tutorial courtesy of UBC in Canada. An excellent Tutorial Tips on how to handle acid/base problems (problem sets developed by S.E. Van Bramer for chemistry and environmental science courses at Widener University.) Acids and Bases by ChemTeam R. H. Logan, Instructor of Chemistry, Dallas County Community College District, North Lake College. Acknowledgements Send Comments to R.H. Logan:

36. Acidbas What are acids and bases? Revised 3/31/96. Return to the AcidBase FAQ list.Return to Home Page. URLhttp//members.aol.com/logan20/acid_bas.html. http://members.aol.com/profchm/acidbas.html

What are Acids and Bases? There are several definitions for each of these terms depending upon how exclusive you make your definition. Traditionally Professor Arrhenius defined these terms as follows: Acid- a substance that produced Hydrogen ion in water solution. The hydrogen ions were hydrated as Hydronium ions. Base- a substance that produced Hydroxide ion in water solution. These definitions were very restrictive. The limitations on these definitions were: 1. The need for water so only aqueous solutions were covered (non-aqueous solutions were excluded) 2. The need for a protic acid since hydrogen ions had to be produced 3. The need for Hydroxide bases You can receive a short biography of Professor Arrenhius Professors Bronsted and Lowry defined these two terms the following: Acid- Proton donor Base- Proton acceptor These definitions are not as restrictive as the first set of definitions. 1. First, there is no need for water although it can be present, it need not be. Therefore non-aqueous systems are included. 2. Secondly, bases do not have to be Hydroxide compounds.

37. Chemistry 1B / Lecture C / Acids N Bases General Chemistry Online FAQ acids and basesA searchable database of frequently asked questions from the acids and bases sectionof General Chemistry Online. acids and bases Frequently asked questions. http://eee.uci.edu/97w/40090/ab.html

Chemistry 1B Lecture C ( Grayce ) Winter 1997 Acidity: Acidity is a measure of the tendency of a molecule to undergo chemical reaction. Since a chemical reaction is just the sudden rearrangement of electron distributions that can occur when molecules come close to one another (collide), the elementary measure of chemical reactivity is the relative appetite for electrons: an acidic molecule is ``hungry'' for electrons, while a basic molecule is not (or equivalently is willing to donate them). Now we can only define chemical reactivity of molecules when we have a standard ``test'' chemical reaction in mind. Consider the problem of measuring the ``flammability'' of materials we could only do this usefully if we defined some standard test to which we would subject all the materials, for example raising the temperature to a certain level for a certain length of time, or holding a lit match to them for a certain length of time, etc. Clearly a material that might be flammable under one test might not be flammable under another, so it is important to have a standard test. The standard elementary test for chemical reactivity is to react the molecule in question with water. For example, to determine whether a molecule acts as an acid we can react it with water acting as a base, e.g.:

38. General Chemistry Online: FAQ: Acids And Bases: What Are Some Natural Acid/base What are some natural acid/base indicators? From a database of frequently askedquestions from the acids and bases section of General Chemistry Online. http://antoine.frostburg.edu/chem/senese/101/acidbase/faq/natural-indicators.sht

Home Common Compounds Exam Guide FAQ Features Glossary Companion Notes Just Ask Antoine! ... Next Question What are some natural acid/base indicators? A visual acid-base indicator is just a weak acid with differently colored acid and conjugate base forms. Flower and leaf pigments often fit this description. For example, take rose petals and crush them with alcohol; you have an acid/base indicator solution. Stew some red cabbage and pour off the juice; you have an acid/base indicator solution. Many indicators can be extracted from plants; others (like phenolphthalein *) and methyl orange are synthetic. Here are a few 'natural' acid/base indicators. For a longer list of house and garden materials that can be used to make acid-base indicators, see a related question Alizarin is an orange dye present in the root of the madder plant; it was used to dye wool in ancient Egypt, Persia, and India. In an 0.5% alcohol solution, alizarin is yellow at pH 5.5 and red at pH 6.8. Several synthetic modifications of alizarin are also used as acid/base indicators. Cochineal is an acid-base indicator made from the bodies of dried female cochineal insects, found in Mexico and Central America. You'll have to grind about 70,000 insects to make one pound of dry indicator. The powder is about 10% carminic acid, which is yellow in acidic solution, and deep violet in alkaline solution. Cochineal solutions are not used much as acid/base indicators these days.

39. The Observable Properties Of Acids And Bases The Observable Properties of acids and bases. The property below identifiesa unique chemical reaction that acids and bases engage in. http://dbhs.wvusd.k12.ca.us/webdocs/AcidBase/Acid-Base-Properties.html

The Observable Properties of Acids and Bases Return to the Acid Base menu The word acid and alkaline (older word for base) are derived from direct sensory experience. Acid Property #1. The word acid comes from the Latin word acere , which means "sour." All acids taste sour. Well known from ancient times were vinegar, sour milk and lemon juice. Aspirin tastes sour if you don't swallow it fast enought. Its scientific name is acetosallicylic acid! Other languages derive their word for acid from the meaning of sour. So, in France, we have acide. In Germany, we have from saure and in Russia, kislota from kisly. Base Property #1. The word "base" has a more complex history (see below) and its name is not related to taste. All bases taste bitter. Mustard tastes bitter. Many medicines, cough syrup is one, taste bitter. This is the reason cough syrups are advertised as having a "great grape taste." The taste is added in order to cover the bitterness of the active ingredient in cough syrup. Acid Property #2. In 1663, Robert Boyle wrote that acids would make a blue vegetable dye called "litmus" turn red.

40. ChemTeam: The Lewis Theory Of Acids And Bases The Lewis Theory of acids and bases. Return to the Acid Base menu. I. Introduction. Onewas his theory of acids and bases. In 1923, he wrote http://dbhs.wvusd.k12.ca.us/webdocs/AcidBase/Intro-to-Lewis-AcidBase.html

The Lewis Theory of Acids and Bases Return to the Acid Base menu I. Introduction Gilbert Newton Lewis is one of the great chemists in history. His greatest discovery may well be the theory of the covalent bond in 1916, but he made many other contributions. One was his theory of acids and bases. In 1923, he wrote: "We are so habituated to the use of water as a solvent, and our data are so frequently limited to those obtained in aqueous solutions, that we frequently define an acid or a base as a substance whose aqueous solution gives, respectively, a higher concentration of hydrogen ion or of hydroxide ion than that furnished by pure water. This is a very one sided definition . . . ." What Lewis wanted was a general definition of an acid and a base, one that was universal no matter what the chemical environment. He know that the current ideas (the Arrhenius theory - dating from the late 1800's and the Bronsted-Lowry theory - announced in January 1923) were not sufficient. In the next 2 pages of discussion, after the above quote, Lewis wrote: "When we discuss aqueous solutions of substances which do not contain hydroxyl [ion], it is simplest to define a base as a substance which adds hydrogen ion. . . . Since hydrogen is a constituent of most of our electrolytic solvents, the definition of an acid or base as a substance which gives up or takes up hydrogen ion would be more general than the one we used before, but it would not be universal."

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