ACIDS DONATE AND BASES ACCEPT POSITIVE CHARGE

Bases are characterized by their bitter taste and slippery feel. Interestingly, bases themselves arc not slippery. Rather, they cause skin oils to transform into slippery solutions of. soap. Most commercial preparations for unclosing drains are composed of sodium hydroxide, NaOH (also known as lye), which is extremely basic and hazardous when concentrated. Bases are also heavily used in industry. Each year in the United States about 25 billion pounds of sodium hydroxide is manufactured for use in the production of various chemicals and in the pulp and paper industry. Solutions containing bases are often called alkaline, a term derived from the Arabic word for ashes al-qalt), a term we met in Section 

Examples of acids, (a) Citrus fruits contain many types of acids, including ascorbic acid, C, H, Og, which is vitamin C. (b) Vinegar contains acetic acid. C2H4O2, and can be used to preserve foods, (c) Many roilet bowl cleaners arc formulated with hydrochloric acid, HCl. 

Examples ofbases. (a) Reactions involving sodium bicarbonate, NaHCQv make baked goods rise, (b) Ashes contain potassium carbonate, KjCO, . (c) Soap is made by reacting bases with animal or vegetable oils. The soap itself, then, is slightly alkaline, (d) Powerful bases, such as sodium hydroxide, KaOH, are used in drain cleaners. 

H r 0 RAAD ocronyin for r ni iiiberinf how ocids and hoses honde protons fioses Accept. Acids Donate 

Consider what happens when hydrogen chloride is mixed into water  

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Acids Donate and Bases Accept Positive Charge... 

ACIDS DONATE AND BASES ACCEPT POSITIVE CHARGE... 

In this case, the water is behaving as a base because its lone pair seeks out and accepts a positive charge (the proton) while the hydrochloric acid, HC1, behaves as an acid because it donates a positive charge to the lone pair. 

Zwitterions are an amphoprotic species and can behave as either an acid or a base. For example, if a strong acid, such as HC1, is added to a solution of an amino acid, the carboxylate-ion-end of the zwitterion accepts the proton from the stronger acid, and the zwitterion is converted into a cationic species. For convenience, let s represent the zwitterionic form, which has one H+ to donate, as HA. The cationic form, which has two H+ ions to donate and has a net positive charge, is represented at H2A+, as can be seen in Figure 12.47. 

Figure 5-4 Schematic Representation of the Addition of Acid (HA) or Base (B") to an Isoelectric Protein. The isoelectric protein has equal numbers of positive and negative charges. The acid HA donates protons, the base B" accepts protons. Source Reprinted with permission from R. Hamm, Colloid Chemistry of Meat, 1972, Paul Parey (in German).

Logs are also used to calculate the pH of acids and bases. Acids love to donate a positive charge (a proton), and are called proton donors. Water, H20, accepts the charge and becomes HsO+. Can you find the formula that is used to calculate pH Do acids have high or low pH values ... 

As we ve seen, the key feature of a Lewis base is a lone pair of electrons to donate. The key feature of a Lewis acid is a vacant orbital (or the ability to rearrange its bonds to form one) to accept that lone pair and form a new bond. In the upcoming discussion, you ll encounter a variety of neutral molecules and positively charged ions that satisfy this requirement. 

The definitions of acid and base that we use now were provided by Brpnsted and Lowry in 1923. In the Br0nsted-Lowry definitions, an acid is a species that donates a proton, and a base is a species that accepts a proton. (Remember that positively charged hydrogen ions are also called protons.) In the following reaction, hydrogen chloride (HCl) meets the Brpnsted-Lowry definition of an acid because it donates a proton to water. Water meets the definition of a base because it accepts a proton from HCl. Water can accept a proton because it has two lone pairs. Either lone pair can form a covalent bond with a proton. In the reverse reaction, H3O is an acid because it donates a proton to CF, and CF is a base because it accepts a proton from H30. ... 

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