1. Introduction to Acids, Bases and Salts

2. Arrhenius Definition of Acids and Bases
Acids produce H+ in aqueous (water) solutions
water
HCl H+ (aq) + Cl- (aq)
Bases produce OH- in aqueous (water) solutions
NaOH Na+ (aq) + OH- (aq)

4. The Hydronium Ion (H30+) Acids produce the H+ ion
This is just a “bare proton” and is very reactive.
It immediately forms a coordinate covalent bond with nearby water molecules to form (H30+).

5. Acids Produce H+ (as H3O+) ions in water
Electrolytes (conduct in solution)
Taste sour
pH is < 7
Corrode metals (see Table J)
React with bases to form salts and water (Neutralization)

6. Bases Produce OH- ions in water Electrolytes (conduct in solution)
Taste bitter, chalky
pH is >7
Feel soapy, slippery
React with acids to form salts and water (Neutralization)

7. Learning Check
Describe the solution in each of the following as: 1) acid 2) base or 3)neutral.
A. ___soda
B. ___soap
C. ___coffee
D. ___ wine
E. ___ water
F. ___ grapefruit

8. Solution Describe each solution as: 1) acid 2) base or 3) neutral.
A. _1_ soda
B. _2_ soap
C. _2_ coffee
D. _1_ wine
E. _3_ water
F. _1_ grapefruit

9. Learning Check Identify each as characteristic of an
A) acid or B) base
____ 1. Sour taste
____ 2. Produces OH- in aqueous solutions
____ 3. Chalky taste
____ 4. Is an electrolyte
____ 5. Produces H+ in aqueous solutions

10. Solution Identify each as a characteristic of an A) acid or B) base
_A_ 1. Sour taste
_B_ 2. Produces OH- in aqueous solutions
_B_ 3. Chalky taste
A, B 4. Is an electrolyte
_A_ 5. Produces H+ in aqueous solutions

11. Some Common Acids See Table K
HCl hydrochloric acid
HNO3 nitric acid
H3PO4 phosphoric acid
H2SO4 sulfuric acid
HC2H3O2 acetic acid

12. Naming Acids (Honors) Binary Acids Hydro __________ ic Acid
(Contain 2 elements only)
Ex: HCl, HBr, H2S, HF
Hydro __________ ic Acid

13. Naming Acids (Honors) Ternary Acids Look at name of polyatomic ion
(Contain hydrogen and a polyatomic ion)
Do NOT start with “Hydro”
Look at name of polyatomic ion
If it ends in “ate” the acid ends in “ic”
If it ends in “ite” the acid ends in “ous”

14. Name These Acids
HBr
HNO3
H3PO4
HNO2
H2C2O4
HClO
HBrO
HClO4
H2S
HIO3

15. Name These Acids HBr = hydrobromic acid HNO3 = nitric acid
H3PO4 = phosphoric acid
HNO2 = nitrous acid
H2C2O4 = oxalic acid
HClO = hypochlorous acid
HBrO = hypobromous acid
HClO4 = perchloric acid
H2S = hydrosulfuric acid
HIO3 = iodic acid

16. Organic Acids Contain carbon
Only one of the hydrogens is “acidic” and dissociates in solution
Ex: Acetic Acid
HC2H3O2 or CH3COOH

17. Naming Bases Name them like any other ionic compound.
Name usually ends in “hydroxide”
Ex: LiOH = lithium hydroxide

18. Some Common Bases See Table L
NaOH sodium hydroxide
KOH potassium hydroxide
Ba(OH)2 barium hydroxide
Mg(OH)2 magnesium hydroxide
Al(OH)3 aluminum hydroxide

19. Important Note There are no “organic bases” (containing carbon).
C2H5OH for example is not a base.
It is an alcohol. The OH on this molecule does not dissociate to form OH- (hydroxide ion)

20. Salts “Salts” are ionic compounds that are not acids or bases.
Metal cation (+) & nonmetal anion (-)
They are electrolytes when dissolved in water
ions dissociate and become mobile
Ex: NaCl, MgSO4, Li2S

21. Learning Check Acid, Base Name or Salt CaCl2 ______ _______________
KOH ______ _______________
Ba(OH)2 ______ _______________
HBr ______ _______________
H2SO4 ______ ________________

22. Answers Acid,Base Name or Salt CaCl2 salt calcium chloride
KOH base potassium hydroxide
Ba(OH)2 base barium hydroxide
HBr acid hydrobromic acid
H2SO4 acid sulfuric acid

23. Dissociation
Dissociation: when a compound splits apart into ions in solution.
How might these dissociate?
H2SO4
KOH

24. Acids React with Metals
See Reference Table J
Metals above Hydrogen on the table will react with acids to form a salt and H2 gas
Single Replacement Reaction
2Zn(s) + 2HCl(aq) ZnCl2(aq) + H2(g)

25. Will an acid react with these metals?
If so complete and balance the single replacement reaction.
Mg + HNO3
Cu + HCl
Ca + H2SO4

26. Answers Mg + 2HNO3 Mg(NO3)2 + H2
Cu + HCl No reaction Cu in below hydrogen on Table J
Ca + H2SO Ca(SO4) + H2

27. Acid, Bases and Metals BBC (good for Indicators)

28. Pure Water is Neutral H2O H+ + OH- H+ OH-
Self Ionization of Water: a small quantity of water molecules in a sample will self ionize.
This results in a small, but equal amount of H+ and OH-
H2O H OH-
Hydrogen Ion = Hydroxide Ion [H+] = [OH-] H+
OH-

29. Self Ionization of Water

30. Acids Increase the H+ concentration As H+ increases, OH- decreases
[H+] > [OH-] H+
OH-

31. Bases Increase the hydroxide ion (OH-) concentration
When OH- increases, H+ decreases
[OH] > [H+]
OH- H+

32. Acidic: [H+] > [OH-] Basic: [H+] < [OH-] Neutral: [H+] = [OH-]
Important Summary
Acidic: [H+] > [OH-]
Basic: [H+] < [OH-]
Neutral: [H+] = [OH-]

34. Determining if it is an Acid or Base
How can you tell if something is acidic or basic?

35. Use an electronic pH meter

36. Use an indicator such as litmus

37. Use pH paper containing universal indicator

38. Acid/Bases Indicators See Table M
Examples:
Litmus
pH range for color change (4.5 – 8.3)
Color change: red to blue
Phenolphthalein
pH range for color change (8 - 9)
Color change: colorless to pink
What color would these be if the
pH = 10?
pH = 3?

39. pH Scale [H+]>[OH-] [H+] = [OH-] [OH-]>[H+]
Neutral
[H+]>[OH-] [H+] = [OH-] [OH-]>[H+]
Acidic
Basic

40. Pretty Hydrangeas
The color of hydrangea flowers depends on the pH of the soil.

41. What is pH?
Tells us the relative quantity of H+ ions (or the acidity) in solution.
The greater the [H+] the lower the pH.

42. Calculating pH pH = - log [H+] From the French pouvoir hydrogene
(“hydrogen power” or power of
hydrogen)

43. [H+] pH
1 x 10-5 M 5
1 x 10-9 M 9
1 x M 11

44. Calculating pOH What if you are given the concentration of a base?
Ex: M LiOH
You need to find the pOH!!

45. pOH pOH = -log [OH-] Ex: .000001M LiOH = 1 x 10-6 pOH = 6
Ex: M NaOH = 1 x 10-4
pOH = 4

46. How can you find pH of a Base?
Easy!!!
pH + pOH = 14
Ex: M LiOH = 1 x 10-6
pOH = 6
pH = 8
Ex: M NaOH = 1 x 10-4
pOH = 4
pH = 10

47. Or the “ion product” of water.Kw
If you know the concentration of one ion you can find the other!
[H+] x [OH-] = 1 x 10-14
This is called the Kw
Or the “ion product” of water.

48. Everything keeps adding up to 14!!
So what is the [OH-] is the [H+] is .001M?
[1 x 10-3] x [OH-] = 1 x 10-14
[OH-] = 1 x 10-11
Everything keeps adding up to 14!!
What’s up with that?

49. Let’s Try It
You have a .001 HCl solution.
Find: [H+], [OH-], pH, pOH

50. Let’s Try It You have a .000000001M NaOH solution.
Find: [H+], [OH-], pH, pOH

51. Equation Summary pH = -log [H+ ] pOH = -log [OH- ]
[H+ ] = 10-pH [OH- ] = 10-pOH
pH + pOH = 14 [H+ ] x [OH- ] = 1x10-14
Acidic solution: pH < 7 pOH > 7
Neutral solution: pH = 7 pOH = 7
Basic solution: pH > 7 pOH < 7

52. pH and pOH game

53. Honors Questions If the pH of a solution is 3.25 find the pOH,
[H+], and [OH-].
If .065 mole of KOH is placed in 20 liters of
water, what is the resulting pH?

54. (Not to be confused with “Chocolate Rain”)
Acid Rain
(Not to be confused with “Chocolate Rain”)

55. Acid Rain Unpolluted rain has a pH of 5.6
It is naturally acidic due to the gases in the air that dissolve in it.

56. Acid Rain
Rain with a pH below 5.6 is “acid rain“

58. pH of Rainwater across United States in 2001

59. Sources of Acid Rain

60. Sources of Acid Rain Power stations Oil refineries
Coal with high S content
Car and truck emissions
Bacterial decomposition, and lightning hitting N2

61. CO2 in the air forms carbonic acid
CO2 + H2O H2CO3
This increases the [H+] of rain
H2CO H+ (aq) + HCO3-(aq)
Reactions with oxygen in air form SO3
2SO2 + O SO3
Reactions with water in air form acids
SO3 + H2O H2SO4 sulfuric acid
NO + H2O HNO2 nitrous acid
HNO2 + H2O HNO3 nitric acid

62. Effects of Acid Rain

63. Effects of Acid Rain
Leaches heavy metals like Al from soil, which kills fish
Fish kills in spring from runoff due to accumulation of large amounts of acid in snow
Dissolves waxy coatings that protect leaves from bacteria
Corrodes metals, textiles, paper and leather

64. Acid Rain Destroys National Monuments
Global Warming: CO2 and Ocean Acidity

65. Acid Rain Site produced by EPA
EPA Website Detailing Acid Rain Causes and Effects as well as Legislation

66. Neutralization Reactions

67. General Reaction

68. Neutralization Forms Water
H OH-  H2O
from acid from base neutral
This “net” reaction for neutralization is found
on Table I. It is an exothermic reaction.

69. Forming a Salt (+) cation from the base (-) anion from the acid
combine to form a salt.
HCl + NaOH NaCl + HOH
Acid + Base Salt + water

70. Neutralization Reactions
These are double replacement reactions
Ions switch partners. Water is formed.

71. Neutralization Reactions
If equal concentrations of hydrogen ion H+ and hydroxide ions OH- are mixed, it results in a neutral solution.
Ex:
.1M LiOH M HCl = Neutral Solution
pH = 7

72. Completing and Balancing Neutralization Equations
Write charges for ions in acid and base.
Switch ion partners. (+ ions stay in front!!)
Do not bring over subscripts except if part of a polyatomic ion!
Criss-Cross charges to balance formulas.
Balance entire equation.
Name the acid, base and salt.

73. You Try It Complete equation and balance formulas Balance equation.
Name acid base and salt
Ex: KOH + H2SO4
Ex: Mg(OH)2 + HNO3

74. Titrations
Purpose:
To determine the concentration of an acid or base through a neutralization reaction.

75. Acid/Base Titration Buret is filled with a “standard solution” of
known concentration.
Erlenmeyer Flask contains
solution of unknown conc..
Indicator (phenolphthalein)
added to the flask.

76. Acid/Base Titrations Slowly “titrate” or drip liquid
into flask from buret until
indicator changes color.
This is the “endpoint”.
Record total volume used
from buret.

77. Titration Formula MA x VA = MB x VB
Molarity Acid x Volume Acid = Molarity Base x Volume Base
At “equivalence point”
Moles H+ = Moles OH-

78. Titration Applet

79. Important Note
Multiply acid/base side of equation by number of H+ or OH- ions it produces when dissociating!!!
Ex:
H2SO4 produces 2 H+ so you would multiply the acid side by “2”

80. You Try It! A 50 ml sample of .2M HCl is neutralized by
75ml of NaOH. What is the conc. of the base?
HCl NaOH
.2M x 50ml = MB x 75ml
MB = .13M

81. You Try It! How much of a .1M H2SO4 solution is
needed to neutralize 50 ml of a .05 KOH
solution?
H2SO4 KOH
2 x .1M x VA = .05M x 50ml
VA = 12.5 ml

82. Titration Demonstration

83. Hydrolysis Opposite reaction to neutralization
Salt + Water Acid + Base

84. Parent Acid/Base
If you know the salt involved you should be able to determine which acid and base it would form if water is added.
Salt + Water Acid + Base
Ex:
NaCl with water (HOH) would form HCl and NaOH

85. You Try It
Name the “parent” acid and base that would be produced from these salts.
Ex: Potassium chloride
Magnesium carbonate

86. pH and Hydrolysis
Salts can yield neutral, acidic or basic solutions depending on what type of acid or base they produce.
SA/SB = Neutral
SA/WB = Acidic
WA/SB = Basic
WA/WB = Undetermined

87. Strength of Acids and Bases
Do they ionize 100%?

88. Strong Acids : Give up H+ easily
Dissociate completely (100%) in water
HCl, HBr, HI, HNO3, H2SO4, HClO4, HClO3

89. Weak acids: (all others)
Hold onto H+
Few molecules dissociate
Ex: HC2H3O2

90. Let’s examine the behavior of an acid, HA, in aqueous solution.
What happens to the HA molecules in solution?

91. 100% dissociation of HA HA H+ Strong Acid A-
Would the solution be conductive?
Oh yeah…

92. Partial dissociation of HA
Weak Acid A-
Would the solution be conductive?
Not really…

93. At any one time, only a fraction of the molecules are dissociated.
HA  H A- HA H+
Weak Acid A-
At any one time, only a fraction of the molecules are dissociated.

94. Acids Ionizing in Water (Strong vs. Weak)
Acid H+ Transfer (Strong vs. Weak)

95. Strong Bases: Dissociate completely (100%) in water
- Group I metal hydroxides (NaOH, LiOH, etc.)
- Some Group II metal hydroxides
Ca(OH)2, Ba(OH)2,
Sr(OH)2
Weak Bases
Only a few ions dissociate
Ex: NH 3 (ammonia)

96. Strength and Reactivity
Acids/bases of the same initial molar concentration can react differently and conduct electricity differently if one is weak and the other strong.
Ex: 2M HCl = Strong Acid,
very conductive very reactive
2M HC2H3O2 = Weak Acid
Weak Conduction
Salad Dressing!!!

97. The Brønsted-Lowry Definition of Acids and Bases
Acid: PROTON DONOR
can donate H+ ions.
Base: PROTON ACCEPTOR
accepts H+ ions.
Broader Definition than Arrhenius

98. Review: Arrhenius Definition of Acids and Bases
Acids produce H+ in aqueous (water) solutions
water
HCl H+ (aq) + Cl- (aq)
Bases produce OH- in aqueous (water) solutions
NaOH Na+ (aq) + OH- (aq)

99. H+ Transfer Acid/base reactions involve “proton transfer”.
The reaction need not occur in water.

100. Follow the H+ H+ leaves one compound and is transferred to another.
Ex: NH H2O NH OH-
Base Acid

101. Conjugate acid/base pairs: formulas differ
by only a hydrogen ion, H+.
The acid on one side becomes the base on
the other side and vice versa.
Ex:
HCl + H2O H3O+ + Cl-
Acid Base Acid Base

102. Conjugate acid
contains one
more H+ in its
formula

105. Amphoteric/Amphiprotic Substances:
Can act as either an acid or a base.
Must have an “H” in formula (to donate)
Must have a free e- pair (to accept a H+)

106. Water is amphoteric
It can donate an H+ or accept an H+
It depends on what it is combined with.

107. to NH3 forming the hydroxide ion (OH-).
Water donates H+
to NH3 forming the hydroxide ion (OH-).
Water accepts H+
from HCl forming the hydronium ion (H3O+).

108. When it can go either way… Amphoteric (amphiprotic) substances
Acting like
a base
Acting like an acid
HCO3-
+ H+
- H+
H2CO3
CO3-2
accepts H+
donates H+

109. Online tutorial on Bronsted/Lowry

110. Dilution Mfinal x Vfinal = Minitial x Vinitial water (solvent) solute
moles of solute remain constant
diluted, Mfinal
Vfinal
molesinitial = molesfinal
Vinitial
concentrated, Minitial
adding water lowers the solute concentration
Mfinal x Vfinal = Minitial x Vinitial

111. Strong/Weak Acid Animation
Acid and Base Tutorial:
Acid Base Quiz
Acid dissociation in water
Acid/Bases Theories
Titration Game
Acid Bases Hydrogen Transfer (Neutralization)