1. © Copyright Pearson Prentice Hall Slide 1 of 35 Acid-Base Theories Bracken Cave, near San Antonio, Texas, is home to twenty to forty million bats. Visitors to the cave must protect themselves from the dangerous levels of ammonia in the cave. Ammonia is a byproduct of the bats’ urine. You will learn why ammonia is considered a base. 19.1

2. © Copyright Pearson Prentice Hall Acid-Base Theories > Slide 2 of 35 Acid-Base Theories > > Properties of Acids and Bases What are the properties of acids and bases? 19.1

3. Slide 3 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > Properties of Acids and Bases Acids Acids taste sour, will change the color of an acid-base indicator, and can be strong or weak electrolytes in aqueous solution. 19.1

4. Slide 4 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > Properties of Acids and Bases Citrus fruits contain citric acid. Tea contains tannic acid. 19.1

5. Slide 5 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > Properties of Acids and Bases Bases Bases taste bitter, feel slippery, will change the color of an acid-base indicator, and can be strong or weak electrolytes in aqueous solution. 19.1

6. Slide 6 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > Properties of Acids and Bases Antacids use bases to neutralize excess stomach acid. The base calcium hydroxide is a component of mortar. 19.1

7. Slide 7 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > Arrhenius Acids and Bases How did Arrhenius define an acid and a base? 19.1

8. © Copyright Pearson Prentice Hall Slide 8 of 35 Acid-Base Theories > > > Arrhenius Acids and Bases Arrhenius said that acids are hydrogen- containing compounds that ionize to yield hydrogen ions (H + ) in aqueous solution. He also said that bases are compounds that ionize to yield hydroxide ions (OH – ) in aqueous solution. 19.1

9. Slide 9 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > 19.1 Arrhenius Acids and Bases Hydrochloric Acid

10. Slide 10 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > Arrhenius Acids and Bases Arrhenius Acids Acids that contain one ionizable hydrogen, such as nitric acid (HNO 3 ), are called monoprotic acids. Acids that contain two ionizable hydrogens, such as sulfuric acid (H 2 SO 4 ), are called diprotic acids. Acids that contain three ionizable hydrogens, such as phosphoric acid (H 3 PO 4 ) are called triprotic acids. 19.1

11. Slide 11 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > Arrhenius Acids and Bases 19.1

12. Slide 12 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > Arrhenius Acids and Bases Arrhenius Bases Hydroxide ions are one of the products of the dissolution of an alkali metal in water. 19.1

13. Slide 13 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > Arrhenius Acids and Bases 19.1

14. © Copyright Pearson Prentice Hall Acid-Base Theories > Slide 14 of 35 Acid-Base Theories > > Brønsted-Lowry Acids and Bases What distinguishes an acid from a base in the Brønsted-Lowry theory? 19.1

15. © Copyright Pearson Prentice Hall Slide 15 of 35 Acid-Base Theories > > > Brønsted-Lowry Acids and Bases The Brønsted-Lowry theory defines an acid as a hydrogen-ion donor, and a base as a hydrogen-ion acceptor. 19.1

16. Slide 16 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > Brønsted-Lowry Acids and Bases Why Ammonia is a Base 19.1

17. Slide 17 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > Brønsted-Lowry Acids and Bases Conjugate Acids and Bases A conjugate acid is the particle formed when a base gains a hydrogen ion. A conjugate base is the particle that remains when an acid has donated a hydrogen ion. 19.1

18. Slide 18 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > Brønsted-Lowry Acids and Bases A conjugate acid-base pair consists of two substances related by the loss or gain of a single hydrogen ion. A substance that can act as both an acid and a base is said to be amphoteric. 19.1

19. Slide 19 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > Brønsted-Lowry Acids and Bases 19.1

20. Slide 20 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > Brønsted-Lowry Acids and Bases A water molecule that gains a hydrogen ion becomes a positively charged hydronium ion (H 3 O + ). 19.1

21. © Copyright Pearson Prentice Hall Acid-Base Theories > Slide 21 of 35 Acid-Base Theories > > Lewis Acids and Bases How did Lewis define an acid and a base? 19.1

22. © Copyright Pearson Prentice Hall Slide 22 of 35 Acid-Base Theories > > > Lewis Acids and Bases Lewis proposed that an acid accepts a pair of electrons during a reaction, while a base donates a pair of electrons. 19.1

23. Slide 23 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > Lewis Acids and Bases A Lewis acid is a substance that can accept a pair of electrons to form a covalent bond. A Lewis base is a substance that can donate a pair of electrons to form a covalent bond. 19.1

24. © Copyright Pearson Prentice Hall Slide 24 of 35 Acid-Base Theories > Lewis Acids and Bases Animation 25 Compare the three important definitions of acids and bases.

25. Slide 25 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > Lewis Acids and Bases 19.1

26. © Copyright Pearson Prentice Hall Slide 26 of 35 Acid-Base Theories >

27. © Copyright Pearson Prentice Hall Slide 27 of 35 Acid-Base Theories >

28. © Copyright Pearson Prentice Hall Slide 28 of 35 Acid-Base Theories >

29. © Copyright Pearson Prentice Hall Slide 29 of 35 Practice Problems for Conceptual Problem 19.1 Problem Solving 19.1 Solve Problem 1 with the help of an interactive guided tutorial.

30. © Copyright Pearson Prentice Hall Slide 30 of 35 1. Which of the following is NOT a characteristic of acids? a.taste sour b.are electrolytes c.feel slippery d.affect the color of indicators 19.1 Section Quiz.

31. © Copyright Pearson Prentice Hall Slide 31 of 35 2. Which compound is most likely to act as an Arrhenius acid? a.H 2 O b.NH 3. c.NaOH. d.H 2 SO 4. 19.1 Section Quiz.

32. © Copyright Pearson Prentice Hall Slide 32 of 35 19.1 Section Quiz. 3. A Lewis acid is any substance that can accept a.a hydronium ion. b.a proton. c.hydrogen. d.a pair of electrons.

33. © Copyright Pearson Prentice Hall Slide 33 of 35 Hydrogen Ions and Acidity To test a diagnosis of diabetic coma, a doctor orders several tests, including the acidity of the patient’s blood. Results from this test will be expressed in units of pH. You will learn how the pH scale is used to indicate the acidity of a solution and why the pH scale is used. 19.2

34. © Copyright Pearson Prentice Hall Slide 34 of 35 Hydrogen Ions from Water a.The reaction in which water molecules produce ions is called the self-ionization of water. 19.2

35. © Copyright Pearson Prentice Hall Slide 35 of 35 Hydrogen Ions from Water a.In the self-ionization of water, a proton (hydrogen ion) transfers from one water molecule to another water molecule. 19.2

36. © Copyright Pearson Prentice Hall Slide 36 of 35 Ion Product Constant for Water How are [H + ] and [OH - ] related in an aqueous solution? 19.2

37. © Copyright Pearson Prentice Hall Slide 37 of 35 Ion Product Constant for Water For aqueous solutions, the product of the hydrogen-ion concentration and the hydroxide-ion concentration equals 1.0  10 -14. Any aqueous solution in which [H + ] and [OH - ] are equal is described as a neutral solution. 19.2

38. © Copyright Pearson Prentice Hall Slide 38 of 35 Ion Product Constant for Water a.The product of the concentrations of the hydrogen ions and hydroxide ions in water is called the ion-product constant for water (K w ). 19.2

39. © Copyright Pearson Prentice Hall Slide 39 of 35 Ion Product Constant for Water a.An acidic solution is one in which [H + ] is greater than [OH - ]. 19.2

40. © Copyright Pearson Prentice Hall Slide 40 of 35 Ion Product Constant for Water a.Unrefined hydrochloric acid, commonly called muriatic acid, is used to clean stone buildings and swimming pools. 19.2

41. © Copyright Pearson Prentice Hall Slide 41 of 35 Ion Product Constant for Water a.A basic solution is one in which [H + ] is less than [OH  ]. Basic solutions are also known as alkaline solutions. 19.2

42. © Copyright Pearson Prentice Hall Slide 42 of 35 Ion Product Constant for Water a.Sodium hydroxide, or lye, is commonly used as a drain cleaner. 19.2

43. © Copyright Pearson Prentice Hall Slide 43 of 35 19.1

44. © Copyright Pearson Prentice Hall Slide 44 of 35 19.1

45. © Copyright Pearson Prentice Hall Slide 45 of 35 19.1

46. © Copyright Pearson Prentice Hall Slide 46 of 35 19.1

47. © Copyright Pearson Prentice Hall Slide 47 of 35 for Sample Problem 19.1

48. © Copyright Pearson Prentice Hall Slide 48 of 35 The pH Concept How is the hydrogen-ion concentration used to classify a solution as neutral, acidic, or basic? 19.2

49. © Copyright Pearson Prentice Hall Slide 49 of 35 The pH Concept a.The pH of a solution is the negative logarithm of the hydrogen-ion concentration. 19.2

50. © Copyright Pearson Prentice Hall Slide 50 of 35 The pH Concept Calculating pH 19.2

51. © Copyright Pearson Prentice Hall Slide 51 of 35 The pH Concept a.A solution in which [H + ] is greater than 1  10 –7 M has a pH less than 7.0 and is acidic. The pH of pure water or a neutral aqueous solution is 7.0. A solution with a pH greater than 7 is basic and has a [H + ] of less than 1  10 –7 M. 19.2

52. © Copyright Pearson Prentice Hall Slide 52 of 35 19.2 The pH Concept

53. © Copyright Pearson Prentice Hall Slide 53 of 35 The pH Concept 19.2

54. © Copyright Pearson Prentice Hall Slide 54 of 35 The pH Concept Calculating pOH 19.2

55. © Copyright Pearson Prentice Hall Slide 55 of 35 The pH Concept pH and Significant Figures 19.2

56. © Copyright Pearson Prentice Hall Slide 56 of 35 19.2

57. © Copyright Pearson Prentice Hall Slide 57 of 35 19.2

58. © Copyright Pearson Prentice Hall Slide 58 of 35 19.2

59. © Copyright Pearson Prentice Hall Slide 59 of 35 19.2

60. © Copyright Pearson Prentice Hall Slide 60 of 35 for Sample Problem 19.2

61. © Copyright Pearson Prentice Hall Slide 61 of 35 19.3

62. © Copyright Pearson Prentice Hall Slide 62 of 35 19.3

63. © Copyright Pearson Prentice Hall Slide 63 of 35 19.3

64. © Copyright Pearson Prentice Hall Slide 64 of 35 19.3

65. © Copyright Pearson Prentice Hall Slide 65 of 35 for Sample Problem 19.3

66. © Copyright Pearson Prentice Hall Slide 66 of 35 Measuring pH What is the most important characteristic of an acid-base indicator? 19.2

67. © Copyright Pearson Prentice Hall Slide 67 of 35 Measuring pH An indicator is a valuable tool for measuring pH because its acid form and base form have different colors in solution. 19.2

68. © Copyright Pearson Prentice Hall Slide 68 of 35 Measurin g pH a.Phenolphthalein changes from colorless to pink at pH 7–9. 19.2

69. © Copyright Pearson Prentice Hall Slide 69 of 35 19.4

70. © Copyright Pearson Prentice Hall Slide 70 of 35 19.4

71. © Copyright Pearson Prentice Hall Slide 71 of 35 19.4

72. © Copyright Pearson Prentice Hall Slide 72 of 35 19.4

73. © Copyright Pearson Prentice Hall Slide 73 of 35 for Sample Problem 19.4

74. © Copyright Pearson Prentice Hall Slide 74 of 35 Measuring pH Acid-Base Indicators 19.2

75. © Copyright Pearson Prentice Hall Slide 75 of 35 Measuring pH 19.2

76. © Copyright Pearson Prentice Hall Slide 76 of 35 Measuring pH a.Universal Indicators 19.2

77. © Copyright Pearson Prentice Hall Slide 77 of 35 19.2 Section Quiz. 1. If the [OH - ] in a solution is 7.65  10 -3 M, what is the [H + ] of this solution? a.7.65  10 -17 M b.1.31  10 -12 M c.2.12M d.11.88M

78. © Copyright Pearson Prentice Hall Slide 78 of 35 19.2 Section Quiz. 2. The [OH - ] for four solutions is given below. Which one of the solution is basic? a.1.0 x 10 -6 M b.1.0 x 10 -8 M c.1.0 x 10 -7 M d.1.0 x 10 -14 M

79. © Copyright Pearson Prentice Hall Slide 79 of 35 3. What is the pH of a solution with a hydrogen- ion concentration of 8.5 x 10 -2 M? a.12.93 b.8.50 c.5.50 d.1.07 19.2 Section Quiz.

80. © Copyright Pearson Prentice Hall Slide 80 of 35 Strengths of Acids and Bases Lemons and grapefruits have a sour taste because they contain citric acid. Sulfuric acid is a widely used industrial chemical that can quickly cause severe burns if it comes into contact with skin. You will learn why some acids are weak and some acids are strong. 19.3

81. © Copyright Pearson Prentice Hall Slide 81 of 35 Strong and Weak Acids and Bases How does the value of an acid dissociation constant relate to the strength of an acid? 19.3

82. © Copyright Pearson Prentice Hall Slide 82 of 35 Strong and Weak Acids and Bases a.An acid dissociation constant (K a ) is the ratio of the concentration of the dissociated (or ionized) form of an acid to the concentration of the undissociated (nonionized) form. 19.3

83. © Copyright Pearson Prentice Hall Slide 83 of 35 Strong and Weak Acids and Bases Weak acids have small K a values. The stronger an acid is, the larger is its K a value. 19.3

84. © Copyright Pearson Prentice Hall Slide 84 of 35 Strong and Weak Acids and Bases a.Strong acids are completely ionized in aqueous solution. a.Weak acids ionize only slightly in aqueous solution. 19.3

85. © Copyright Pearson Prentice Hall Slide 85 of 35 Strong and Weak Acids and Bases a.In general, the base dissociation constant (K b ) is the ratio of the concentration of the conjugate acid times the concentration of the hydroxide ion to the concentration of the base. 19.3

86. © Copyright Pearson Prentice Hall Slide 86 of 35 Strong and Weak Acids and Bases a.Strong bases dissociate completely into metal ions and hydroxide ions in aqueous solution. b.Weak bases react with water to form the hydroxide ion and the conjugate acid of the base. 19.3

87. © Copyright Pearson Prentice Hall Slide 87 of 35 Strong and Weak Acids and Bases 19.3

88. © Copyright Pearson Prentice Hall Slide 88 of 35 Calculating Dissociation Constants How can you calculate an acid dissociation constant (K a ) of a weak acid? 19.3

89. © Copyright Pearson Prentice Hall Slide 89 of 35 Calculating Dissociation Constants To find the K a of a weak acid or the K b of a weak base, substitute the measured concentrations of all the substances present at equilibrium into the expression for K a or K b. 19.3

90. © Copyright Pearson Prentice Hall Slide 90 of 35 Calculating Dissociation Constants Acid Dissociation Constant a.The dissociation constant, K a, of ethanoic acid is calculated from the equilibrium concentrations of all of the molecules and ions in the solution. 19.3

91. © Copyright Pearson Prentice Hall Slide 91 of 35 Calculating Dissociation Constants 19.3

92. © Copyright Pearson Prentice Hall Slide 92 of 35 Calculating Dissociation Constants 19.3

93. © Copyright Pearson Prentice Hall Slide 93 of 35 Calculating Dissociation Constants Base Dissociation Constant a.The dissociation constant, K b, of ammonia is calculated from the equilibrium concentrations of all of the molecules and ions in the solution. 19.3

94. © Copyright Pearson Prentice Hall Slide 94 of 35 Calculating Dissociation Constants Concentration and Strength 19.3

95. © Copyright Pearson Prentice Hall Slide 95 of 35 19.5

96. © Copyright Pearson Prentice Hall Slide 96 of 35 19.5

97. © Copyright Pearson Prentice Hall Slide 97 of 35 19.5

98. © Copyright Pearson Prentice Hall Slide 98 of 35 19.5

99. © Copyright Pearson Prentice Hall Slide 99 of 35 for Sample Problem 19.5 Problem Solving 19.23 Solve Problem 23 with the help of an interactive guided tutorial.

100. © Copyright Pearson Prentice Hall Slide 100 of 35 19.3 Section Quiz. 1. H 2 S is considered to be a weak acid because it a.is insoluble in water. b.ionizes only slightly. c.is completely ionized. d.is dilute.

101. © Copyright Pearson Prentice Hall Slide 101 of 35 19.3 Section Quiz. 2. Calcium hydroxide, Ca(OH) 2, is a strong base because it a.has a large K b. b.has a small K b. c.forms concentrated solutions. d.is highly soluble in water.

102. © Copyright Pearson Prentice Hall Slide 102 of 35 19.3 Section Quiz. 3. If the [H + ] of a 0.205M solution of phenol (C 6 H 5 OH) at 25ºC is 2.340  10 -6, what is the K a for phenol? Phenol is monoprotic. a. K a = 2.67 x 10 -11 b. K a = 1.14 x 10 -5 c. K a = 5.48 x 10 -12 d. K a = 1.53 x 10 -3

103. © Copyright Pearson Prentice Hall Slide 103 of 35 19.3 Section Quiz. 4. The K a of three acids is given below. (1) 5.1  10 –3 (2) 4.8  10 –11 (3) 6.3  10 –5 Put the acids in order from the strongest acid to the weakest acid. a.1, 3, 2 b.2, 3, 1 c.3, 1, 2 d.2, 1, 3

104. © Copyright Pearson Prentice Hall Slide 104 of 35 5. The K b of four bases is given below. (1) 7.41 x 10 -5 (2) 1.78 x 10 -5 (3) 4.27 x 10 -4 (4) 4.79 x 10 -4 Put the bases in order from the strongest base to the weakest base. a.2, 3, 4, 1 b.2, 1, 3, 4 c.4, 3, 1, 2 d.1, 4, 3, 2 19.3 Section Quiz.

105. © Copyright Pearson Prentice Hall Slide 105 of 35 Neutralization Reactions Excess hydrochloric acid in the stomach can cause heartburn and a feeling of nausea. Antacids neutralize the stomach acid and relieve the pain of acid indigestion. You will learn what a neutralization reaction is. 19.4

106. © Copyright Pearson Prentice Hall Slide 106 of 35 Acid-Base Reactions What are the products of the reaction of an acid with a base? 19.4

107. © Copyright Pearson Prentice Hall Slide 107 of 35 Acid-Base Reactions a.In general, the reaction of an acid with a base produces water and one of a class of compounds called salts. 19.4

108. © Copyright Pearson Prentice Hall Slide 108 of 35 Acid-Base Reactions a.Reactions in which an acid and a base react in an aqueous solution to produce a salt and water are generally called neutralization reactions. 19.4

109. © Copyright Pearson Prentice Hall Slide 109 of 35 Acid-Base Reactions 19.4

110. © Copyright Pearson Prentice Hall Slide 110 of 35 Titration What is the endpoint of a titration? 19.4

111. © Copyright Pearson Prentice Hall Slide 111 of 35 Titration a.The process of adding a known amount of solution of known concentration to determine the concentration of another solution is called titration. The point of neutralization is the end point of the titration. 19.4

112. © Copyright Pearson Prentice Hall Slide 112 of 35 Titration a.When an acid and base are mixed, the equivalence point is when the number of moles of hydrogen ions equals the number of moles of hydroxide ions. 19.4

113. © Copyright Pearson Prentice Hall Slide 113 of 35 19.6

114. © Copyright Pearson Prentice Hall Slide 114 of 35 19.6

115. © Copyright Pearson Prentice Hall Slide 115 of 35 19.6

116. © Copyright Pearson Prentice Hall Slide 116 of 35 19.6

117. © Copyright Pearson Prentice Hall Slide 117 of 35 for Sample Problem 19.6

118. © Copyright Pearson Prentice Hall Slide 118 of 35 Titration a.The solution of known concentration is called the standard solution. Indicators are often used to determine when enough of the standard solution has been added to neutralize the acid or base. The point at which the indicator changes color is the end point of the titration. 19.4

119. © Copyright Pearson Prentice Hall Slide 119 of 35 Titration Acid solution with indicator Added base is measured with a buret. Color change shows neutralization. 19.4

120. © Copyright Pearson Prentice Hall Slide 120 of 35 Titration Simulation 26 Simulate the titration of several acids and bases and observe patterns in the pH at equivalence.

121. © Copyright Pearson Prentice Hall Slide 121 of 35 Titration 19.4

122. © Copyright Pearson Prentice Hall Slide 122 of 35 19.7

123. © Copyright Pearson Prentice Hall Slide 123 of 35 19.7

124. © Copyright Pearson Prentice Hall Slide 124 of 35 19.7

125. © Copyright Pearson Prentice Hall Slide 125 of 35 19.7

126. © Copyright Pearson Prentice Hall Slide 126 of 35 for Sample Problem 19.7 Problem Solving 19.33 Solve Problem 33 with the help of an interactive guided tutorial.

127. © Copyright Pearson Prentice Hall Slide 127 of 35 19.4 Section Quiz 1. When a neutralization takes place, one of the products is always a.carbon dioxide. b.a salt. c.sodium chloride. d.a precipitate.

128. © Copyright Pearson Prentice Hall Slide 128 of 35 2. In a titration, 45.0 mL of KOH is neutralized by 75.0 mL of 0.30M HBr. What is the concentration of the KOH solution? a.0.18M b.0.60M c.0.25M d.0.50M 19.4 Section Quiz

129. © Copyright Pearson Prentice Hall Slide 129 of 35 3. How many moles of HCl are required to neutralize an aqueous solution of 2.0 mol Ca(OH) 2 ? a.0.5 mol b.1.0 mol c.2.0 mol d.4.0 mol 19.4 Section Quiz

130. © Copyright Pearson Prentice Hall Slide 130 of 35 19.4 Section Quiz 4. In which of the following neutralization titrations of 1-molar solutions of H 2 SO 4 and NaOH will the equivalence point be reached at the very end of the additions? H 2 SO 4 (aq) + 2NaOH(aq)  Na 2 SO 4 (aq) + 2H 2 O(aq) a.200 mL of H 2 SO 4 is slowly added to 100 mL of NaOH b.200 mL of H 2 SO 4 is slowly added to 200 mL of NaOH c.100 mL of H 2 SO 4 is slowly added to 200 mL of NaOH d.100 mL of H 2 SO 4 is slowly added to 100 mL of NaOH

131. © Copyright Pearson Prentice Hall Slide 131 of 35 Salts in Solution The chemical processes inside a living cell are very sensitive to pH. Human blood is normally maintained at a pH very close to 7.4. You will learn about chemical processes that ensure that the pH of blood is kept near 7.4. 19.5

132. © Copyright Pearson Prentice Hall Slide 132 of 35 Salt Hydrolysis When is the solution of a salt acidic or basic? 19.5

133. © Copyright Pearson Prentice Hall Slide 133 of 35 Salt Hydrolysis In general, salts that produce acidic solutions contain positive ions that release protons to water. Salts that produce basic solutions contain negative ions that attract protons from water. 19.5

134. © Copyright Pearson Prentice Hall Slide 134 of 35 Salt Hydrolysis a.In salt hydrolysis, the cations or anions of a dissociated salt remove hydrogen ions from or donate hydrogen ions to water. 19.5

135. © Copyright Pearson Prentice Hall Slide 135 of 35 Salt Hydrolysis 19.5

136. © Copyright Pearson Prentice Hall Slide 136 of 35 Salt Hydrolysis 19.5

137. © Copyright Pearson Prentice Hall Slide 137 of 35 Salt Hydrolysis a.To determine whether a salt solution is acidic or basic, remember the following rules: 19.5

138. © Copyright Pearson Prentice Hall Slide 138 of 35 Salt Hydrolysis a.Vapors of the strong acid HCl(aq) and the weak base NH 3 (aq) combine to form the acidic white salt ammonium chloride (NH 4 Cl). 19.5

139. © Copyright Pearson Prentice Hall Slide 139 of 35 Salt Hydrolysis 19.5

140. © Copyright Pearson Prentice Hall Slide 140 of 35 NH 4 Cl pH 5.3 NaCl pH 7 CH 3 COONa pH 5.3 Salt Hydrolysis a.Universal indicator solution has been added to each of these 0.10M aqueous salt solutions. 19.5

141. © Copyright Pearson Prentice Hall Slide 141 of 35 Buffers What are the components of a buffer? 19.5

142. © Copyright Pearson Prentice Hall Slide 142 of 35 Buffers a.A buffer is a solution of a weak acid and one of its salts, or a solution of a weak base and one of its salts. a.The pH of a buffer remains relatively constant when small amounts of acid or base are added. b.The buffer capacity is the amount of acid or base that can be added to a buffer solution before a significant change in pH occurs. 19.5

143. © Copyright Pearson Prentice Hall Slide 143 of 35 Buffers a.Buffer of Ethanoic Acid and Sodium Ethanoate Adding H + produces additional ethanoic acid. Adding OH - produces additional ethanoate ions. The pH changes very little. 19.5

144. © Copyright Pearson Prentice Hall Slide 144 of 35 Buffers 19.5

145. © Copyright Pearson Prentice Hall Slide 145 of 35 Buffers Animation 26 Discover the chemistry behind buffer action.

146. © Copyright Pearson Prentice Hall Slide 146 of 35 Buffers 19.5

147. © Copyright Pearson Prentice Hall Slide 147 of 35

148. © Copyright Pearson Prentice Hall Slide 148 of 35

149. © Copyright Pearson Prentice Hall Slide 149 of 35 Conceptual Problem 19.2

150. © Copyright Pearson Prentice Hall Slide 150 of 35 for Conceptual Problem 19.2 Problem Solving 19.39 Solve Problem 39 with the help of an interactive guided tutorial.

151. © Copyright Pearson Prentice Hall Slide 151 of 35 1. Which of the following reactions would most likely yield a basic salt solution? a.strong acid + weak base b.weak acid + weak base c.strong acid + strong base d.weak acid + strong base 19.5 Section Quiz.

152. © Copyright Pearson Prentice Hall Slide 152 of 35 19.5 Section Quiz. 2. Choose the correct words for the spaces. A buffer can be a solution of a _________ and its _________. a.weak acid, salt b.strong acid, salt c.weak acid, conjugate base d.weak base, conjugate acid