About acids and bases

Acids and bases are a big part of organic chemistry but the emphasis is much different from what you may be familiar with from your general chemistry course Most of the atten tion m general chemistry is given to numerical calculations pH percent loniza tion buffer problems and so on Some of this returns m organic chemistry but mostly we are concerned with the roles that acids and bases play as reactants products and catalysts m chemical reactions We 11 start by reviewing some general ideas about acids and bases... 

The same G N Lewis who gave us electron dot formulas also suggested a way of think mg about acids and bases that is more general than the Brpnsted-Lowry approach Where Brpnsted and Lowry viewed acids and bases as donors and acceptors of protons (positively charged) Lewis took the opposite view and focused on electron pairs (negatively charged) According to Lewis an acid is an electron pair acceptor and a base is an electron pair donor... 

New Chapter 1 has been retitled Structure Deter mines Properties to better reflect its purpose and has been rewritten to feature a detailed treatment of acids and bases Rather than a review of what stu dents learned about acids and bases m general chemistry Sections 1 12-1 17 discuss acids and bases from an organic chemistry perspective... 

Tabulating Values for K and Kb A useful observation about acids and bases is that the strength of a base is inversely proportional to the strength of its conjugate acid. Consider, for example, the dissociation reactions of acetic acid and acetate. 

Arrhenius theory explained a lot about acids and bases, but it did not explain everything. Not all bases release hydroxide ions. In fact, one of the most commonly used bases—baking soda... 

You learned about acids and bases in your previous chemistry course. In this chapter, you will extend your knowledge to learn how the structure of a compound determines whether it is an acid or a base. You will use the equilibrium constant of the reaction of an acid or base with water to determine whether the acid or base is strong or weak. You will apply your understanding of dissociation and pH to investigate buffer solutions solutions that resist changes in pH. Finally, you will examine acid-base titrations that involve combinations of strong and weak acids and bases. 

Of the concepts that chemists use to make sense of chemical transformations, ideas about acids and bases are among the most fruitful. Nearly all of the hetero-lytic reactions that we shall be considering can be thought of as acid-base processes it is therefore appropriate to begin our discussion of the chemical properties of organic compounds with a review of these ideas and of their applications in organic chemistry. 

The above two equations describing the behavior of Bronsted acids and bases are not strictly correct because a Bronsted acid does not just dissociate, it donates a proton to something which accepts a proton. The proton does not just dissociate and Boat around in solution but is always attached to something. Furthermore a Bronsted base does not just find a proton to accept it accepts a proton from a Bronsted acid. Thus acidity and basicity are paired behavior— you can t have one without the other. This is the most common misconception about acids and bases and leads to die greatest amount of difficulties when trying to apply die principles of acidity and basicity to real reactions. 

This exercise will help you familiarise yourself with some of the terms involved in talking about acids and bases. 

The ABC activities provide a meaningful way for students to learn new concepts. The activities are specifically designed to create in the students a sense that the topics under discussion represent concepts that they need to know. As Veronica and Leroy explore water uses in their community, they discover (with the help of their teacher) that they cannot complete their research without learning about acids and bases, new concepts (for them) to which they had never given serious thought. This discovery initiates a series of activities designed to help students understand the usefulness of information about acids and bases and other relevant concepts. In one activity, the students perform inventories of the acid content and characteristics of the foods in their... 

Which statement about acids and bases is not true ... 

Acids, and to a lesser extent bases, are part of our conversations, advertisements, and concerns. Headlines and television screens inform and persuade us about acid reflux, acid rain, cleaning compounds, and antacids (Figure 11.1). As you work your way through this unit and learn about acids and bases, you will find yourself looking at their presence in the world around you with a new awareness. 

Compared with neutral water, acidic solutions contain a higher concentration of hydronium ions. Basic solutions contain a lower concentration of hydronium ions. Therefore, the dissociation of water provides another way of thinking about acids and bases. An acid is any compound that increases [H30+] when it is dissolved in water. A base is any compound that increases [OH ] when it is dissolved in water. (See Figure 10.11.)... 

Visit the Chemistry Web site at chemistrymc.com to find links about acids and bases. 

Many students have two very common misconceptions about acids and bases. First, they believe that all acids are extremely corrosive, capable of dissolving a person the way the acids that they see in movies are. Second, they believe that all bases are harmless, because they can be used to neutralize deadly acids. The truth is that not all acids are hazardous and not all bases are safe. All of the acids and bases that you encounter in the chemistry lab should be handled with care, especially if you are unsure of how strong they are. 

One of the most interesting things about acids and bases is that they can react with each other in such a way as to render each other harmless. A neutralization reaction occurs when aqueous solutions of an acid and a base react with each other to produce a salt (ionic compound) and water. The general format for neutralization reaction is this acid + base salt + water... 

Gay-Lussac reached an important conclusion about acids and bases. What was it ... 

Outline Arrhenius ideas about acids and bases, (a) How did he define the following terms acid, base, neutralization (b) Give an example that illustrates each term. 

To find out more about acids and bases, visit the Glencoe Science Web site. 

Acids and bases are as familiar as aspirin and milk of magnesia although many people do not know their chemical names—acetylsalicylic acid (aspirin) and magnesium hydroxide (milk of magnesia). In addition to being the basis of many medicinal and household products, acid-base chemistry is important in industrial processes and essential in sustaining biological systems. Before we can discuss acid-base reactions, we need to know more about acids and bases themselves. 

Analyze if a recipe calls for flour, salt, sugar, bran cereal, milk, an egg, and shortening or vegetable oil, would you use baking soda or baking powder Explain. For more information about acids and bases in cooking, visit glencoe.com. 

What can flowers tell us about acids and bases Actually, some flowers can tell us whether the soil they are growing in is acidic or basic. For example, in acidic soil, bigleaf hydrangea blossoms will be blue in basic (alkaline) soil, the flowers will be red. What is the secret The pigment in the flower is an acid-base indicator. 

Up to this time, the ideas about acids and bases focused on the use of water as a solvent. Water is a protic solvent because it has the capacity to donate protons. Water is polar, which means it has a slight electric charge (see Chapter 10 for more details). Gilbert Lewis considered the case of a nonpolar, or nonprotic, solvent and how dissolution might occur in non-aqueous solvents where polar species cannot be dissolved. 

Because many acidic and basic solutions occur in nature, observations about acids and bases date back hundreds of years. One of the most important observations is that a solution cannot be both acidic and basic at the same time. Mixing an acid and a base leads to a reaction known as neutralization, in which the resulting solution is neither acidic nor basic. To understand the origins of this neutralization, we might start with the definitions of acid and base. Acid solutions contain H3O ions, and bases contain OH ions. So for a solution to be both an acid and a base simultaneously, it would need to contain both of these species. Looking at those ions, it should be easy to see why this is not feasible. Hydronium ions and hydroxide ions combine readily to form water ... 

Hydrochloric acid, HCl, is one of the first acids a beginning chemistry student learns. This strong acid reacts with most metals and forms hydrogen ions. Many experiments use HCl as a reactant. It is easy to spot the sloppy chemistry student, just look at his or her clothes and shoes. If they have a lot of tiny holes in their clothes, chances are good they don t have moths, but have splashed an acid or base on themselves while pouring. This is why chemists wear laboratory coats and eye goggles for protection. In this chapter, we will find out more about acids and bases and why they are so fierce. 

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