This document provides an overview of acids and bases according to different theories: 1. Arrhenius theory defines acids as producing hydrogen ions in water and bases as producing hydroxide ions. 2. Brønsted-Lowry theory defines acids as hydrogen ion donors and bases as hydrogen ion acceptors. 3. Lewis theory focuses on electron pair donation and acceptance between reactants. It also discusses the pH scale, ion product constant of water, and using indicators to determine if a solution is acidic, basic, or neutral.

1. Chapter 19 “ Acids, Bases, and Salts ”

6. Acids Affect Indicators, by changing their color Blue litmus paper turns red in contact with an acid (and red paper stays red).

7. Acids have a pH less than 7

8. Acids React with Active Metals Acids react with active metals to form salts and hydrogen gas: HCl (aq) + Mg (s) -> MgCl 2(aq) + H 2(g) This is a single-replacement reaction

9. Acids React with Carbonates and Bicarbonates HCl + NaHCO 3 NaCl + H 2 O + CO 2 Hydrochloric acid + sodium bicarbonate salt + water + carbon dioxide An old-time home remedy for relieving an upset stomach

10. Effects of Acid Rain on Marble (marble is calcium carbonate ) George Washington: BEFORE acid rain George Washington: AFTER acid rain

11. Acids Neutralize Bases HCl + NaOH -> NaCl + H 2 O - Neutralization reactions ALWAYS produce a salt (which is an ionic compound ) and water. -Of course, it takes the right proportion of acid and base to produce a neutral salt

19. Bases Affect Indicators Red litmus paper turns blue in contact with a base (and blue paper stays blue). Phenolphthalein turns purple in a base.

20. Bases have a pH greater than 7

21. Bases Neutralize Acids Milk of Magnesia contains magnesium hydroxide, Mg(OH) 2 , which neutralizes stomach acid, HCl. 2 HCl + Mg(OH) 2 MgCl 2 + 2 H 2 O Magnesium salts can cause diarrhea (thus they are used as a laxative) and may also cause kidney stones.

22. Acid-Base Theories

24. Hubert N. Alyea (1903-1996)

26. Svante Arrhenius (1859-1927)

30. Organic Acids (those with carbon) Organic acids all contain the carboxyl group, (-COOH), sometimes several of them. CH 3 COOH – of the 4 hydrogen, only 1 ionizable The carboxyl group is a poor proton donor, so ALL organic acids are weak acids . (due to being bonded to the highly electronegative Oxygen )

32. Johannes Brønsted Thomas Lowry (1879-1947) (1874-1936) Denmark England

37. Gilbert Lewis (1875-1946)

38. - Page 593

45. - Page 596

50. - Page 599

51. - Page 600

53. How to measure pH with wide-range paper 1. Moisten the pH indicator paper strip with a few drops of solution, by using a stirring rod. 2.Compare the color to the chart on the vial – then read the pH value.

54. Some of the many pH Indicators and their pH range

64. Strong Acid Dissociation (makes 100 % ions)

65. Weak Acid Dissociation (only partially ionizes)

70. - Page 610

78. - Page 614

91. Aspirin (which is a type of acid) sometimes causes stomach upset; thus by adding a “buffer”, it does not cause the acid irritation. Bufferin is one brand of a buffered aspirin that is sold in stores. What about the cost compared to plain aspirin?

92. End of Chapter 19