1. Introduction to Acids and Bases
Chapter 19
Sections 1, 2, plus some of 3 and 4
Honors Chemistry
Dr. Knorr
Adapted from

2. Some Common Acids HCl hydrochloric acid HNO3 nitric acid
H3PO4 phosphoric acid
H2SO4 sulfuric acid
HC2H3O2 acetic acid (vinegar)
lemon juice

3. Acids Electrolytes Taste sour Corrode metals React with many bases to
form salts and water

4. Some Common Bases NaOH sodium hydroxide KOH potassium hydroxide
Mg(OH)2 magnesium hydroxide Al(OH)3 aluminum hydroxide
NH3 ammonia

5. Bases Taste bitter, chalky Are electrolytes Feel soapy, slippery
React with many acids to
form salts and water

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

7. Brønsted-Lowry Acids and Bases
Acids donate H+ in aqueous solutions
water
HCl H+(aq) + Cl- (aq)
Bases accept H+ in aqueous solutions
NH3 + H2O NH4+(aq) + OH- (aq)
All Arrhenius A/B are B-L A/B

8. Lewis Acids and Bases Acids accept electron pairs in aqueous solutions
Bases donate electron pairs in aqueous solutions
H F H F
H N B F H N B F

9. Conjugate Acids and Bases
A conjugate acid-base pair is related by
loss/gain of one hydrogen ion.
NH3 + H2O NH4+(aq) + OH- (aq)
Base acid conjugate acid conjugate base
gain H+
lose H+

10. pH Indicates the acidity [H+] of the solution pH = - log [H+] [H+] pH
1 x 10-5 M 5
1 x 10-9 M 9
1 x M 11

11. pOH Indicates the basicity (aka alkalinity) [OH-] of the solution
pOH = - log [OH-]
[OH-] pOH
1 x 10-5 M 5
1 x 10-9 M 9
1 x M 11

12. pH Range [H+]>[OH-] [H+] = [OH-] [OH-]>[H+]
Neutral
[H+]>[OH-] [H+] = [OH-] [OH-]>[H+]
Acidic
Basic

13. Why 0  14? Autoionization of water H2O H+ + OH-
In pure water, [H+] = [OH-] = 1 x 10-7 M
so [H+] x [OH-] = 1 x 10-14
Another important relationship:
pH + pOH = 14

14. pH, pOH, [H+], and [OH-] [H+] pH pOH [OH-] 1 x 10-5 M 5 9 1 x 10-9 M
2.4
3.98 x 10-3 M
11.6
2.51 x M

15. Acids H+ OH- Increase H+ HCl (g) H+ (aq) + Cl- (aq)
More [H+] than water alone
As H+ increases, OH- decreases
[H+] > [OH-]
water H+
OH-

16. pH of Some Common Acids gastric juice 1.0 lemon juice 2.3 vinegar 2.8
orange juice 3.5
coffee
milk

17. Acids Strong Acids (the big 7): HCl, HBr, HI, HNO3, H2SO4,
HClO4, HClO3
Example:
HCl(aq) H+ (aq) + Cl- (aq)
**Strong acids completely ionize

18. Acids Weak acids: HC2H3O2, HF, (and all others) Example:
HF(aq) H+ (aq) + F-(aq)
** Weak acids ionize only slightly

19. Bases Increase the hydroxide ions (OH-) NaOH (s) Na+(aq) + OH- (aq)
More [OH-] than water, [OH-]
When OH- increases, H+ decreases
[OH] > [H+]
OH- H+

20. pH of Some Common Bases blood 7.4 tears 7.4 seawater 8.4
milk of magnesia 10.6
household ammonia 11.0

21. Bases Strong Bases (the big 8) Example: Group I metal hydroxides
Heavier group II metal hydroxides
Ca(OH)2, Ba(OH)2, Sr(OH)2
Example:
NaOH(aq)  Na+ (aq) + OH- (aq)
**Strong bases completely ionize

22. Bases Weak Bases Example: NH3(aq) +H2O NH4+ (aq) + OH-(aq)
NH 3 (ammonia)
Example:
NH3(aq) +H2O NH4+ (aq) + OH-(aq)
** Weak bases ionize only slightly

23. Neutralization Reactions
When STRONG acids and STRONG bases are mixed in the right amounts, the resulting solution is neutral.
NaOH (aq) HCl(aq) NaCl(aq) H2O(l)
base acid salt water
Ca(OH)2 (aq) HCl(aq) CaCl2(aq) + 2H2O(l)
base acid salt water
**An acid/base reaction is a special form of a double replacement reaction

24. Neutralization
The cation from the base and the anion from the acid combine to form a salt.
Simultaneously, H+ and OH- combine to produce water.
NaOH(aq) HCl(aq) NaCl(aq) H2O(l)
H OH  H2O (or HOH)
from acid from base water
Na Cl  NaCl
from base from acid salt

25. Learning Check AB1
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

26. Solution AB1 Describe each solution as: 1) acid 2) base or 3) neutral.
A. _1_ soda
B. _2_ soap
C. _1_ coffee
D. _1_ wine
E. _3_ water
F. _1_ grapefruit

27. Learning Check AB2
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

28. Solution AB2
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

29. Learning Check AB3 Acid, Base Name or Salt
CaCl ______ _________________
KOH ______ _________________
Ba(OH)2 ______ _________________
HBr ______ _________________
H2SO4 ______ __________________

30. Solution AB3 Acid, Base Name or Salt CaCl2 salt calcium chloride
KOH base potassiuim hydroxide
Ba(OH)2 base barium hydroxide
HBr acid hydrobromic acid
H2SO4 acid sulfuric acid