1. Acids and Bases

2. Definitions of Acids
Arrhenius Acid-any substance that produces hydrogen ions (H+) when dissolved in water.
Bronsted Lowry acid-any substance that donates protons to form hydronium ions (H3O+)
Examples of acids: HCl, HNO3, H2SO4, HC2H3O2

3. Electrolytes
Solutions that conduct an electric current efficiently contain strong electrolytes.
Strong electrolytes are substances that completely ionize in water.
Acids that ionize completely and are classified as strong electrolytes are also classified as strong acids.

4. Strong acids The following are classified as strong acids:
HCl, HBr, HI, H2SO4, HNO3,HClO3, HClO4
All other acids are classified as weak acids (they do not ionize completely in water).
Note: a classification of strong vs weak acid is independent of the concentration-for example, a strong acid can be very dilute and a weak acid can be very concentrated.

5. Properties of Acids Taste sour React with metals
Conduct electricity (to some degree based on strength)
pH<7
Turn litmus red
Turn phenolphthalein colorless

6. Definitions of Bases
Arrhenius Base-any substance that produces hydroxide ions (OH-) when dissolved in water.
Bronsted Lowry Base- any substance that accepts protons.
Examples of bases: NaOH, Ca(OH)2, Mg(OH)2, NH3

7. Bases as electrolytes
Bases are also classified as strong vs weak, based on the degree of ionization.
The strong bases (strong electrolytes) are: (group 1A hydroxides, Sr(OH)2 and Ba(OH)2 )
All other bases are classified as weak bases.

8. Properties of Bases Taste bitter Feel slippery Conduct electricity
pH>7
Turn litmus blue
Turn phenolphthalein pink

9. Naming Acids Binary acids- consist of hydrogen and one other element.
Use the prefix –hydro and change the ending of the element to –ic.
Example: HCl hydrochloric acid
HBr hydrobromic acid
H2S hydrosulfuric acid

10. Naming acids
Oxyacids-consist of hydrogen, oxygen, and one additional element.
If the polyatomic ion ends in –ate, change the ending to –ic.
If the polyatomic ion ends in –ite, change the ending to –ous.
Example: H2SO4 sulfuric acid (diprotic)
H2SO3 sulfurous acid (diprotic)
HNO nitric acid (monoprotic)
HNO2 nitrous acid (monoprotic)
H3PO phosphoric acid (triprotic)

11. Naming bases
All bases consist of the hydroxide ion and one additional element.
Name the element followed by hydroxide.
Example: NaOH sodium hydroxide
Ca(OH)2 calcium hydroxide
Al(OH)3 aluminum hydroxide

12. NaOH is an example of a(n)10
Acid
Base
Neither 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

13. A substance that is a proton acceptor is a(n)10
Acid
Base
neither 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

14. HCl is an example of a(n)
Acid
Base
Neither 10 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

15. Lemon juice is an example of a(n)
Acid
Base
Neither 10 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

16. A substance that is a proton donor is an example of a(n)
Acid
Base
Neither 10 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

17. Drain cleaner is an example of a(n)
Acid
Base
Neither 10 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

18. Vinegar is an example of a(n)
Acid
Base
Neither 10 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

19. Water is an example of a(n)
Acid
Base
Neither 10 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

20. A substance that turns litmus red is a(n)
Acid
Base
Neither
Both 10 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

21. A substance that conducts electricity is a(n)
Acid
Base
Neither
Both 10 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

22. Which of the following is the correct name of HBr?10
Hydrobromic acid
Bromic acid
Bromous acid
Bromine hydroxide 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

23. Which of the following is the correct name of H2CO3?10
Hydrocarbonic acid
Carbonic acid
Carbonous acid
Hydrogen coarbon oxide 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

24. Which of the following is the correct name of Ba(OH)2?10
Hydrobaric acid
Baric acid
Barous acid
Barium hydroxide 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

25. Autoionization of Water
Because water is amphoteric, water can transfer a proton from one water molecule to another to produce a hydronium ion and a hydroxide ion.
2 H2O (l) <---> H3O+ (aq) + OH- (aq)
Experiments show that at 25oC,
[H3O+] = [OH-] = 1x10-7 M

26. Autoionization of Water
In any aqueous solution at 25oC, no matter what it contains, the product of [H3O+] and [OH-] must always equal
1x There are three possible situations:
1. A neutral solution, where [H3O+] = [OH-]
2. An acidic solution, where [H3O+] > [OH-]
3. A basic solution, where [H3O+] < [OH-]

27. Sample Problems
Calculate the [H3O+] and [OH-] for each of the following and state whether the solution is acidic, basic, or neutral.
a) 1.0 x 10-5 M OH-
b) 1.0 x 10-7 M OH-
c) 10.0 M H30+

28. The pH Scale
Because [H3O+] is typically very small, the pH scale provides a convenient way to represent solution acidity.
The pH scale is a logarithmic scale used to quantitatively represent the strength (concentration) of an acid.

29. Calculating pH pH = -log[H3O+]
The greater the concentration of the hydrogen ion (H+), the stronger the acid and the lower the pH.
For a solution where [H3O+] =
1.0 x 10-7 M, pH = 7.00

30. Sample Problems What is the pH of a solution in which [H+] = 1 x 10-2?
Which is more concentrated?
pH=2

31. Similar log Scales
Similar log scales are used for representing other quantities:
The pOH scale is a logarithmic scale used to quantitatively represent the strength (concentration) of a base.
pOH = -log[OH-]
The greater the concentration of the hydroxide ion (OH-), the stronger the base and the lower the pOH.
**** pH + pOH = 14.00

32. Practice Problems
Calculate the pH and pOH of solutions with the following concentrations and classify as acidic, basic, or neutral.
[OH-] = 1 x 10-9
[H+] = 1 x 10-7
[H+] = 1 x 10-4
[OH-] = 1 x 10-2

33. pH Scale

34. Indicators and pH
Indicators are substances that change color depending on the concentration of hydrogen ions (H+) in a solution.
Litmus and phenolphthalein are examples of indicators.
Indicators can be used to determine the pH of a solution.

35. A solution with a pH of 3 is10
Acidic
Basic
Neutral 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

36. Which of the following is an expected pH for a sample of lemon juice?10 3 6 7 10 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

37. A substance with a pH of 12.7 is a(n)
Acid
Base
Neither
Both 10 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

38. A solution with a [H+] =1x 10-5 has a pH of9 14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

39. A solution with a pH of 8 has a pOH of10 2 6 8 14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

40. A solution with a [OH-]=1x10-3 has a [H+] =11
1 x 1011
1 x 10-11 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

41. Neutralization Reactions
Neutralization reactions occur when acids react with bases and produce a salt and water.
A salt is an ionic compound consisting of the positive ion of the base and the negative ion of the acid.
Example: HCl + NaOH  NaCl + H2O
acid base salt water
If the [H+] = [OH-], the resulting solution will be neutral (pH=7).
Neutralization reactions are a specific type of double displacement reaction.

42. What salt is formed? HCl + KOH  H3PO4 + NaOH  Ca(OH)2 + H2SO4 
Mg(OH)2 + HF 
HNO3 + NaOH 

43. Titration
A titration is a method for determining the concentration of a solution by reacting a known volume of that solution with a solution of known concentration.
The reaction that takes place is a neutralization reaction.

44. Procedure for carrying out titrations.
A measured volume of an acid or base is added to a beaker or flask.
A buret is filled with a solution of known concentration (titrant).
The solution of known concentration is added until the solution in the beaker has been completely neutralized.
This point is called the equivalence point.

45. Titrations Continued
You will recognize the equivalence point because the indicator will change colors at this point.
This is also referred to as the end point of the titration.
The volume that is added to reach this point is used to calculate the unknown molarity.

46. Example
25.0 mL of HCl is titrated to the endpoint with 50.0 mL of 2.0 M NaOH. What is the molarity of the HCl?
M x V = M x V
X (25.0) = 2.0 (50.0)
X= 4.0 M

48. Pre-lab: Which is the most effective antacid?
What makes an antacid effective?
How does the antacid affect the acid?
How will you determine which antacid is most effective at neutralizing the stomach acid?